If you’re completely new to git then you might want to learn a little about its concepts and workflows. The Atlassian Tutorials are concise and very well written. A bit longer, but very useful, is the Pro Git book - chapters 2 and 3 are a good bootstrapping resource. These, and many other, illustrative and interactive online tutorials on git can be found as well:
One very important concept in git is branching, and there’s a very nice tutorial on that in particular:
There are also very nice GUIs for managing git repositories available. These will not be covered in this tutorial (partly because it’s a good idea to learn the commands, but also because most of you are likely to be logging into lxplus) but you may want to have a look at them while your code is compiling. You some popular GUIs (gitkraken is a good cross platform example; sourcetree works very well on a Mac). They can make working with git much easier once you’re working locally.