It's not hard. Take a measurement from the center of the axle to the center of the bolt for the swing arm. Both sides should be the same. When you install the tire back on, adjust the adjuster bolts to get the tire back to the same distance. If the belt is tight when you do that, tighten everything up, double check it all, and take it out for a test ride.
If the belt is a bit slack, just adjust it until it's tight and make sure the distance between the swing arm bolts (pivot point) and the axle is the same for both sides.