Learn to use a tool that your developers use - e.g. an IDE
I've been learning git! Git is a popular source control system. It is usually paired with GitHub, a source code repository.
It can be run from the command line (which is what I'm doing, and what I'd recommend for beginners) but there are also clients for it such as GitExtensions and SourceTree.
I tried to draw a picture of my learnings. Here it is!
I hope that makes a little bit of sense!
P.S. I'm going away for the weekend, which means I'm going to be behind a few days! But there will be more to come, I may even catch up :)