Pull the rear drive and driveshaft off. Slide the ujoint back. Remove old boot and slip in the new boot, put rear of boot on swingarm. Lube the splines(Moly 60 Paste) on the motor output and driveshaft, slip driveshaft into ujoint while holding front of ujoint up with a long screwdriver (be careful not to tear boot) once driveshaft in ujoint, slip it onto the output shaft and put front of boot in place. Lube splines on rear drive. Put rear drive into swingarm, put wheel in place.....
That is one job that really benefits from having Small Hands!
I know it's overkill for Just the boot, but if you can pull the entire swing arm out, then the rear portion of the boot is a sinch to install... Otherwise you just have to have patience while popping it onto the lip, on the swing arm.
Likewise, for the front... just pull it over the lip on the engine case, using your bare hands.