Here are all the Git commands I used last week, and what they do.
Sam Corcos

Git is a very useful but also a highly complex versioning system. The short-tutorials may help with starting working with the git, but in order to use it properly in your team and for your needs, you need to understand it in detail (in particular how branching/merging works). Otherwise, you may end up using git as a tool, but with outdated, SVN-like processes.

Unfortunately, learning the git details goes beyond an article on medium, but fortunately, there is an excellent free e-book written on the topic:

Second and third chapters are particularly important since they both cover the basics (but in more detail than fast-tutorials), and git branching concept. It helped me immensely to understand the context for commands — what should I use to implement a git-process that I need, something that I was not able to find in git-help nor in short recipes on the net.

The chapters are also not too long, so one does not have to loose too much time reading it.