There is a bottom end walk through from bigred350x he does a pretty thorough job of showing you through it. In all reality, the whole transmission is 2 chunks that just lift straight out. The rods and forks under it can stay, pull the drum though and swap the needle roller. You can do as little as take it all apart and clean it and re assemble it with fresh seals, or you can go through every single ear, clip, polish forks and rods, weld the crank, change bearings, etc. How far do you wanna go? Basically if you just want it back together and maybe put some bolt on parts then keep it simple. If you know the motor will eventually get pretty wild, do the trans and anything you can afford.