You really appreciate versioning when several people come up to you all at once with different bugs from different iterations of your code and you don’t have a versioning system in place. A first step in that process is using Git tags. (There’s more than one way to implement versions, but this is one way.)
In his post I will summarize what I gathered from the Atlassian Git tutorial that had lots of really great examples and explanations. I’ll assume you’ve already configured your Git installation and account, but aren’t sure where to go from there. I’ll also assume you’re using linux.