Handholding needed! Test Site Issues

Actually, everything is updated to 2.9.2.

I’ve spent the last few months working on a new version of my website and am ready to move the test to the root. After backing up my database, I simply moved the files and, of course, everything blew up. The only thing I could see was the home page and couldn’t log in to fix links, etc. So I restored everything and am ready to read the directions ;-).

I’ve looked at every video, post, etc. and am now bleary-eyed and my brain is fried. And still can’t find exactly what I’m looking for.

I just need to know the best way to move finished test site to root, and still manage to keep old posts. Is there anything I need to do in the test site before moving (this is what *feels* right), or is there a coding nightmare ahead of me?

Example: test site: https://testsite.mysite.com/test
Just want to move the new layout to: https://mysite.com

Thanks for any help out there. I thought I’d have this done this weekend … oh well