In Darktide there are 4 currencies:

- Ordo Dockets (which you mostly won't have to worry about and will at some point be swimming in it)
- Requisitorium Coins (The weekly mission reward)
- Plasteel (the can/barrel looking things)
- Diamantine (the glowing rectangle things)
- Aquila (the real life currency)

The important point is that you should always pick up all Materials you come across in your missions, always. They're a shared commodity that will be given to all Teammates at the end of your missions.

As for an explanation for each resource:
Ordo dockets are just your normal kind of money, they will get you weapons from the Armory Exchange, outfits and skins if you are willing to spend them on that (which i personally only recommend once you have nothing else to spend them on.)

Requisitorium Coins are the currency you unlock once you reach Trust Level 11. Sire Melk will give you 5 Weekly missions that you mostly complete by just playing the game, there are some that might take a longer time than others or are harder to complete, but you have the options to reroll them at any time.

Plasteel is a more common resource, there are small and large stashes scattered around the mission both in the open and in the chests. Depending on the mission difficulty there is a different amount of Plasteel and Diamantine.
From Difficulty 2 to 5 (Uprising to Damnation in order) the missions will contain 205, 265, 440, 805 Plasteel in total, however if you do not come across it in your natural progression in your mission it is not worth searching it desperately.

Diamantine is a rarer resource, but just like Plasteel spawns throughout the Map and in chests.
And just like Plasteel the harder the mission the more resources you will find.
The mission in order of difficulty will contain 40, 125, 195, 300 Diamantine.

If you're looking for Resources aswell as level your character quickly, i recommend starting to run Level 3 missions as soon as possible, aswell as being consistent with it. Take advantage of modificators of the missions if they affect Enemy spawn amounts over quickplay.
Faster missions over the Bonuses from quickplay.

Something I see a lot of people do is waste their Ammo and in the worst scenario Health against Poxbursters, and it's frustrating to see, as they're most likely the easiest Enemy to deal with.

If you see someone already taking care and preparing to engage the Poxburster, let them deal with it, DO NOT SHOOT, it will just hurt your teammate and endanger your mission.
The Easiest way to deal with it is to pull out your melee weapon, wait for it to jump at you and once it's in the air push it away from you. Once that is done just dash backwards and it will (in most cases) explode. There are situations sometimes (in my own experience) where they will get back up again, however these are more exceptions than the norm.
Quick Reminder: They also deal damage to your enemies and not just teammates, take advantage of this if possible, push them into crowds.

The same is possible with Dogs, you can push them back in the air in case you don't have sufficient Dodge charges or no time to charge an attack.
Once you pushed them you can charge your attack and kill them quickly.
If there is a dog on your teammate, do not go for melee unless you're out of ammo, shoot them ASAP.

Grimoires are a bonus-objective just like scriptures, however they do pack a lot more of a punch.
Grimoires reduce your maximum health over time, there is a way to get an advantage by using Wounds as far as I am aware, however I will not claim this as true (I will do some research on this.)

Because you're playing a Teambased game, before you consider picking up a Grim, ask in the chat if everyone is okay with picking it up, because the reduced maximum health can be a threat to your Mission and might cause you to fail.

There are always 2 Grims per map, divided into sections, there's one book in a section, sections of Maps are divided by group-loading zones, drops or similar obstacles.

As of Patch 1.2.2 there is still a bug where one if not both Grims simply do not spawn and it's an annoyance, however not the downfall of everything.

In Darktide one source besides the Medicae Station is the Healthpack, it's an AOE placable supply randomly found around the Map.
I recommend using them once you do not have access to a Medicae Station or it doesn't have a charge anymore and you or your team is actively in danger.
Healthpacks restore 500 Healthpoints across Teammates or stay for 5 minutes.

If your entire team asks for ammo (as Darktide by nature does't have an indicator of how much ammo everyone has) and you have an Ammo-Crate, throw it down, it holds 4 charges, enough to fill up all of the ammo for every teammate once.
However it does not have to be used this way, if there are as an example two Psykers without weapons, both of the other teammates could use the Ammo-Box twice to fully fill up their Ammo-Pouches.

Please always put them in places all of your Teammates can reach easily and out of harms way.
If you're behind up a drop and use one, I will personally judge you.

Simply said: Do Not.

Longer explanation:
While some of you like the challenge of engaging in the fight with a Daemonhost, there is no benefit in doing so.
Unless it's accidental do not wake it up and avoid it, there is always a second way around it, they're the equivalent to witches in L4D2.
You do not get Bonus XP, Money or ANYTHING for defeating it.

To correctly read the situation I will explain the stages a Daemonhost will go through.

It will start off dormant, on the ground in a Fetal Position crying in your ear and everything, this Phase is entire Harmless and if you run around it all will be good.
The next stage it will enter is the warning stage, that's where it will float above the ground. Do NOT shoot at it or step close or it will be angered. There is a forgiveness mechanic (you can shoot it once in this state without it being angered, for if it's a stray bullet in a horde or something) however it would be wise to not test it.
The last stage is Angered, where it will attack either the Person that dealt the most damage or the one that is closest to it, once it is attacking a person it will not relent until that person is downed.
Afterwards it will search another target, it will only disappear once 2 people are dead and will have to respawn at the next respawn point.

Tip: You can let yourself be downed by other sources, in case you're heroic and not the carry of the team to avoid them getting downed and killed for better chances of succeeding the mission.
Any deaths on the team will satisfy the Daemonhost, not just its own.

Bullgryns and Zealots have both special skills to deal with them and to fight them, however if neither of them are willing to skill into them or do not want to engage, simply walk past. I beg you.

I beg of you just walk past, it's just a waste of time.