I've done two and i'm not a pro. It isn't really hard it just takes patience. It would be best to get an upholstery manual. To greatly help putting the new one on you need measurements from the old top. Some i remember are location of the rear bow and wooden tack strips location. These require stappling so you want them in the right place the first time. I just did a 76 beetle that had no top and the manual really helped. It is a very rewarding job for someone to do themselves.