It depends on your skillset. Are you already familiar with development in general? Or linux?
For Linux yiu should know the basics of how to use it, basic commands, like mount, ls, cd, package managers for your distro, build programs from source etc.
Then you probably need to be familiar with git, if you aren’t already
For contributing to open source games, well they could be written with different languages or engines, so you should familiar with them. And a good first step is bulding them from source!
And for your gamedev journey , if you want to stay truly open source you can try godot, with a python like syntax, and not hard to learn the basics and no royalties to pay.
You need just to make sure you are comfortable with linux cli, then you learn the stuff the more you use it.
Building from source depends on the project. Usual linux way is:
./configure make make installBut that you always need to check the project you wanna build documentation. Since there are different build systems, and some project could be built on a different way.
Given the times where microslop github is being enshtittified (i started to call it slophub) you can use any of the other, it’s up to you (i started to use more and more codeberg), anyway to learn git, you need just make sure to use from cli, so any of the project hosting sites is fine (not even totally necessary, you can have your own project just locally, without remotes, but using on of the above, but in this case you will not deal with remotes, so is a good idea to use one of them, just stick with the cli).
When I said truly open source i was talking about the tools used, but of course i’ll appreciate if you do OO.SS stuff! :)
I would suggest you to use the integrated Godot IDE, especially as beginner, since gamedev is switching between ui part of the engine to set various stuff and coding, so having everything in a single application is much easier. And the godot code editor is also pretty good, give it a try first!!
Anyway setting up godot is one of the easisest things to do :D just download the binary file , make it executable, and run it.
Any question feel free to drop a DM or reply here.