Having Trouble with Git Branching

[KingJigglypuff]

I'm unsure whether or not I'm doing something wrong, but I wanted to give Forge a try, and I already have the original WebUI, so I followed the instructions for using the CMD to switch branches, but upon trying to pull (via git pull), I get an error about divergent branches. Should I progress with what the error says (IE: specifying a git config), or do I need to do something else instead?

If I do need to follow what the error message says, should I merge, rebase, for fast-forward?

[KingJigglypuff]

I think I'll just save myself the trouble and start from scratch, as any attempts to resolve conflicts just result in more issues.