Best way to do minor upgrades 8.03 to 8.04

I have a new SuiteCRM deployement running on Linux Centos 7 server. It was set up by my Upwork system guru quickly and it works well. Now, I want to implement the 8.04 upgrade from 8.03 myself and understand how to do these minor upgrades as they occur. I am not a git expert but I would like to ask the community how best to set this up for future upgrades. There is only the server deployment, I have no repository. Some issues I think are important:

  1. the 8.04 has 2000+ changes from 8.03 so we’re not doing that by hand.
  2. Simply copying over a new 8.04 is not my preferred way because it is not elegant in the sense we have the Git changes so I’d like to use that and not do a full code copy if that isn’t necessary.

Should I simply create a repo from the existing code then apply the changes? My server is backed up nightly on AWS so I am not concerned about messing up while testing things out. thank for advice.