The main uses of your Tardis can be for transportation, a home and perhaps even a battle ship. The Tardis can hold as many people as you want as long as they can fit in the interior. Below I will list all of its key features and more, so enjoy!

Key Features:
Exterior/Interior (Bigger on the inside!)
Sonic Screwdriver compatible
Seats (To rest your butt.)
Interior Console
Flying!
Play music via Gramophone (Refer to 'Interior Console' section)
Lock/unlock Tardis doors
Turn invisible
Teleportation, be The Doctor and dematerialise with your Tardis. Sp00ky!
Sadly, you cannot time travel.

Controls for the Tardis:
Press E anywhere on the interior console that isn't a button to enter Tardis flight (Not to be confused with the flightmode button)
Press R to initiate flightmode. (Same as using flightmode button)
WASD to move around.
Space to move up, while Ctrl moves you down.
You can also look up and hold W in that direction, it'll make you move a lot faster. (Same with downwards)
Hold shift to fly REALLY fast!
Left click to teleport towards your aim position.
Right click to toggle invisibility.
Press E again to go back to the interior.
Alternatively, you can press ALT+E from outside the Tardis to go straight into flightmode and vice versa.

The interior console contained within the Tardis is what you'll use to mainly use to operate it. Below is a list of what each and every button does. If there is a button excluded from this, it's probably because the button doesn't do anything without something else being active first, OR its used in a certain order (Refer to advanced)

Isomorphic Security System - When enabled, only you can use Tardis. Please note people can bypass this by linking with your Tardis via screwdriver, although they'll only be able to teleport, phase and lock/unlock the Tardis. I'm pretty sure Falcos Prop Protection helps with that though. (Used in multiplayer)

Wibbly Lever - Lock/Unlock doors (Same as left clicking with screwdriver)

Phase Controller - Toggles your Tardis invisibility. Keep in mind it will make a sound when you turn this on, although turning it off won't create a sound. (You can also use Sonic Screwdriver to toggle invisibility.

Self Repair - Allows the Tardis to restore its health to 100% only when everyone has exited it.

Flightmode Lever - Toggles the Tardis flying mode on/off.

Programmable Flight - Allows you to save a set of coords on the map so you can go back there later via teleportation. To do this, press E on the typewriter (Programmable Flight Console), as this will open up a console. Click 'New' and save it as whatever you want, preferably the location you're setting it for. Make sure you save it as your current location, then you can click 'Upload' to set your destination.

Monitor - Allows you to select a location anywhere on the map surface (Top-down view) so you can teleport to it when you're ready via the Space Time Throttle. Some maps have low skybox, so teleportation may be screwed up.

Hostile Action Displacement System (HADS) - When enabled, if the Tardis takes damage, it will automatically dematerialise. One way to bring it back is with your sonic screwdriver, so make sure you've linked up. The other way is to simply be inside the Tardis when it dematerialises, and use the space-time throttle or any other conventional method of teleporting it.

Power - Turns the Tardis on/off, useful for disabling everything in the Tardis that's enabled (E.g. Flightmode, HADS, etc.)

Atom Accelerator - Change the spin direction of the Tardis while its flying. Default spin mode is 'Counterclockwise'.

Space Time Throttle - Confirm your teleport destination by flipping this, it will initiate dematerialisation.

Fast-Return Protocol - Goes back to your previous destination. Space Time Throttle isn't needed.

Locking Down Mechanism - Locks the Tardis in place (Not to be confused with Wibbly Lever). Only way to move the Tardis again is by disabling it or using your physgun to manipulate it.

Gramophone - Allows you to play music. You can either select from the preset music, directly from the show Doctor Who, or you can play your own music from a designated URL.

This section is mainly about some things you can do with the Tardis that it doesn't do by itself.


Wiremod - This addon allows you to construct some amazing contraptions. Some of the things you can do is record how much health your Tardis has while you're outside the Tardis. To do this, you will need the following:

-HUD Indicator (In Wiremod)
-Your Tardis

Once you've got these, it's time to set the options. Set your A value to 0 and your B value to 100. Tick the box with 'Show In My HUD' and show value as percent. The rest of the options are purely for decoration and that.
Done all of that? Excellent. Place your hud indicator down. I preferably place it in my Tardis where I can easily do things with it. Search up Wire in the Wiremod tab, it'll come up with one result. With the tool selected, link up A on the Hud Indicator to Health on the Tardis interior or the exterior.
Congrats, if it is working, you should be able to see the HUD Indicator on your screen.

Wiremod Link


Model Manipulator - This addon allows you to change the model of props/NPCs/yourself. If you know where I'm going with this, you'll realise you can use addon to change the model of your Tardis exterior! Simply right click the model you wish to use and then left click the Tardis! Keep in mind some models cause the new modelled Tardis to half sink into the ground, but it still works it's just that certain model.

I won't list the creator of the addon, because I don't know who originally made it and there are lots of addons out there.


Falco's Prop Protection - This addon allows you to protect your props from other players. It will prevent players from picking up your owned entities and they won't be able to use it, unless you add them to buddies. This means that you can prevent people from using your Tardis via Sonic Screwdriver, effectively preventing them from locking/unlocking, toggling invisibility and teleporting it. However, you will still need to toggle Isomorphic Security Systems to stop them from using your buttons, AND sadly admins can bypass this if they allow themselves to.
Falco's Prop Protection Link


For The Tardis Itself - If you take too much damage and reach 0% while in flightmode, your Tardis will begin to spiral out of control, flying all over the area. Press R to turn off the flightmode or just flip the switch itself. Doing this will allow you to do an emergancy landing!


SubMaterial - This addon allows you to change the material in a certain section of an entity. This comes especially useful for decorating your Tardis and making more like 'home'. If you wish to change the Tardis exterior, scroll through the options that appear when you look at the Tardis. If it looks around the same colour, you can replace it with your material. If it doesn't change, then it's either the wrong type of Tardis or you have a material that doesn't work.

Pay close attention to what it's showing you when you select it, as you may end up changing the wrong material in a certain section. You can always revert the material back by right clicking. Don't forget you can change the interior too!
SubMaterial

Advanced Flight Mode is an option in the Tardis settings that you can enable. It allows you to press multiple buttons to initiate dematerialisation, much like how The Doctor presses buttons and flips switches in the show. Below is a list of instructions on how to use this mode, although I personally like keeping this mode disabled.

To enable Advanced Flight Mode, go to Options -> Doctor Who -> Tardis -> Tick the box with Advanced Mode

First of all, you'll need to set your destination in the Programmable Flight or the Monitor.
Secondly, you'll need to press E on the Helmic Regulator.
Thirdly, the Locking-Down Mechanism (Physical Lock when its seen in chat.)
Then you use the Time Rotor Handbrake.
And finally, you flip the Space-Time throttle and kapow, you go through time and space! (Well, not really, mainly just space since you can't travel through time in Gmod :P)

Keep in mind, each time you press the button, you'll hear a noise depending on if its correct or not. Make sure you don't get it incorrect, or you'll start over again!

The Sonic Screwdriver is a must have in every Time Traveler's arsenal. It allows you to lock/unlock doors, making it quite useful in certain scenarios. Not only that, but it'll also interact with the Tardis.
If you want the link to the Sonic Screwdriver addon and what it does (As Dr. Matt explains), go to here: Sonic Screwdriver Link

Of course, I'd still like to list some interesting things for your own convenience and others.

Tardis - The Sonic Screwdriver does a number of interesting things with the Tardis. Using left click on your Tardis makes it lock/unlock itself (Similar to Wibbly Lever), right clicking makes the Tardis go invisible (Much like Phase Controller). Holding ALT+Left click with your Sonic out allows you to link with the Time Machine. Left clicking the ground while you're linked will set its desired destination, and R will confirm it once you've set your location. Of course, pressing R without setting a destination will make the Tardis teleport to your AimPos. Other people can do this with your Tardis also, but if you install FPP (Falco's Prop Protection) onto the server, only admins will be able to link to it and interract using the Sonic Screwdriver.

Door STool - This addon is compatible with the Sonic Screwdriver, allowing you to open/close these doors when they're spawned. Using left click will open them, while right click will close them. Enjoy! ADDON: Door STool Link

WAC Aircraft - One thing you can do with the Screwdriver is toggle the engines on WAC Aircraft. So you can remotely start your plane's engines while running away from angry natives, shut down the engines of enemy helicopters so that they crash from lack of power, or troll the local airport by making all the aircraft power up and crash into everything. Just aim at your desired craft and hold left click to turn the engines on/off. For multiple craft, you have to trigger them individually, and it doesn't have enough range to affect high-altitude aircraft, in which case the Half-Life 2 RPG would work better. Unless your the kind of prick who would just noclip after the target to keep them from reactivating their engines, In which case you should be banned for that.
- By Gofastmike

gm_bluehills_test3 - Certain Gmod maps have world buttons and objects that you can interract with. The Sonic Screwdriver is capable of activating these map objects. One of those maps in particular, gm_bluehills, has several 'vault' doors in its underground area. Using your Sonic Screwdriver on these doors will cause them to open/close. This is useful if people cover the buttons with props, trying to restrict you from the door access.

I hope this guide has helped you and whatnot, if you have any questions or suggestions, post it in the comments below.

This guide is no longer being updated besides some small edits due to a lack of interest on my part.

Happy dematerializing Time Travelers!