Hey there! Welcome, and do ask any time you're wondering about anything, there are no stupid questions
It helps to hop on our IRC if you're idle or on a computer for some other reason and can stay connected in the background. Discussion happens more or less randomly but over time it can give you a good feel for what's going on, while the forum can be a bit more quiet. Most the talk is on Slack but the main channel there is bridged to IRC as well as Discord. Actually
joining Discord might be even better as there you get the chat logs more readily than via IRC (and there's a mobile app if that's more your style).
Sometimes you'll hit the right timing and there's active discussion while you're around, often that'll be some topic of development that could use more volunteers. Pretty much
everything needs more volunteers, but thanks to time zones, busy schedules, and so on it is often hard to connect the right people at the right times
In the meantime grab the source code and see if you can get the game running that way. There are a few tutorials that could be useful, especially if you'll be around when Google Code-In starts. There will be a bunch of teenage students trying to learn the very basics and since you're already at the level of considering GSOC you should have no problem picking up a few things over the next 3 weeks that could be useful to help teacher students starting out at the entry level of programming. After November 28th or so our IRC will explode with activity
For tutorials try out
https://github.com/Terasology/TutorialWorldGeneration,
https://github.com/Terasology/TutorialAssetSystem, or
https://github.com/Terasology/TutorialNUI - if anything at all is unclear please ask! We love feedback and if you find things you think you could improve please do!