You need some basic familiarity with using a terminal or command prompt. While there are generally graphical user interfaces for most commands, the terminal or command prompt can be quicker to use, and will use less system resources.
While you don't need to be a QGIS ninja, it will be helpful if you have at least heard of it.
Get yourself an account on GitHub!
Git(Hub)- see https://git-scm.com/book/en/v2/Getting-Started-Installing-Git for options
A reasonable text editor, not Microsoft Word or Notepad. You could try atom if you're stuck for ideas