Crosspost from the Discord, but still thought it'd be good to share here! Reminder that the wiki has moved to https://terrariamods.wiki.gg/wiki/Metroid_Mod and the Fandom wiki is no longer being updated.

Anyone is allowed to develop the wiki at https://terrariamods.wiki.gg/wiki/Metroid_Mod and community effort is the best tool for making a great wiki, so never be afraid to help!
You can sign up for an account (which is free and very easy!) which helps you keep track of things and for collaborating with other editors.

First, by clicking on any redlink you find on the wiki, you will immediately be directed to the editor for making that page. Alternatively, if you look on the box to the left of the wiki called Tools, there's a link to New page which will send you to a special page where you can determine the type and name of the page you want to make. For our purposes, most of the time the type of page will be a Main page and you will want to start the name off with Metroid Mod/ in order to keep it within our mod's wiki.

To edit an existing page, at the top of the page you should see a tab that says Edit. Just click on that and you can start editing!

The editor can seem a little overwhelming at first, or perhaps too barebones to really do anything beyond simple text. However, there are a lot of tools to make things easier, like linking to other pages, items, recipes, and more. Here are some simple tools to get started:

will create a link to any page on the entire wiki. The text field is what plaintext is shown on the actual hyperlink. The text field is optional.
will create a link to another page in this mod's wiki. The text field is what plaintext is shown on the actual hyperlink. The text field is optional.
will list all the recipes that will craft item.
will list all recipes that use that item as an ingredient.

There are plenty of other useful tools like these, called Templates, which smarter people have made for us to use on the wikis. Additionally, they tend to have other parameters so you can configure them as you want. It's good to know as much about these templates as you can because they are the bread and butter of editing. Lookup in the wiki search bar and click on it to read documentation. I highly suggest doing this for any Template you come across. Feel free to look at other wikis to get an idea of how to use them. Just be warned, the Terraria wiki is very advanced and they have some templates auto-complete, or entire templates that only exist on that wiki, so try checking other mod wikis like Calamity for resources. If the Template documentation page shows up in the search bar on the mod wiki, then it should be available to use. Lastly, never be afraid to ask others for help, or to even try googling. You may want to use the term "MediaWiki" instead of "Terraria wiki" because that's the backbone of these wikis.

Here's the fun part! Writing pages is a very personal thing and what varies between good writing will vary between editors. Always put useful and truthful information wherever possible, and write what you think is relevant to the topic of the page.

If you're wondering how to get game data or similar, play the mod! Use a mod like Cheat Sheet to help, it has a lot of useful tools (just remember to only upload things currently in the mod). Alternatively, the mod source code on github (https://github.com/Scooterboot/MetroidMod) will have a lot of useful info if you know how to read it. It also has all the images used in the game.

Similarly to making normal pages, you may come across redlinks which ask for images for specific things. This will bring you to a page where you can simply upload a file and it should immediately put the correct name needed on the destination file for it to go where it needs to. However, there are some stipulations for uploading that the greater Terraria Mods wiki asks. Firstly, all files need to be in the form of so that we can differentiate our media from other mods (.ext depends on what you're uploading, of course). For example, if I wanted to upload a file for the Arm Cannon, I would need to make sure the destination file (not the source file that I'm uploading to the wiki) says in order for it to automatically work when I use it for editing anything related to the Arm Cannon. Other than that, just make sure that when you upload the file, you go to the editor for that page and put or in there so that it goes to the mod's correct media page. This makes it easier to access for updating sprites and whatnot.

Lastly, don't be worried! You can look at other pages on this wiki or even other wikis such as the Terraria wiki or Calamity wiki for examples on how to write pages. However, this doesn't mean you need to copy their formats or styles 1-to-1. It takes a lot of effort to make high-quality and easily readable pages, and most pages should realistically go through an iterative process before they're even close to being "finished". At this current stage of the wiki, I believe a focus on creating simple and digestible pages which easily allow users to either find what they're looking for easily or to understand the topic of a page without overwhelming either the editor or the user is a good goal.