They go into it a little bit in this video here. A trick I use with worn out springs is to just zip tie them together so they all support each other and are pulled tighter toward each other. The video gives you a little info on replacing the springs if need be.
Hog ring pliers and hog rings for the seat covers will be a must. Legendary sells rebuild kits as well as the vinyl covers. There are other seat foam manufacturers out there like PUI but I can tell you first hand that they aren't molded correctly and don't fit as well as Legendary. You can make them work but it takes extra effort.
