Youtube is full of videos. My advice is to watch as many as you possibly can and ask questions when you have them. You're going to see people do it wrong and right so don't trust just any single source. You can also look up paintless dent removal and using a stud gun like others have suggested.
FWIW, one of the best mechanics I have ever known (and a pretty good body guy) did a roof re-skin on his hatch (apparently it rusted from the inside out which is weird). He came out with a good result but it took him forever and was a ton of work. He removed the entire roof at the factory joints and patched the replacement one in the same way. He said he would never do it again and he's not someone that is shy about large projects.
'91 GT 5 Speed