What I always did when I had one, was first make sure it is unplugged..then use a framing square against your fence and run the blade along the lenght of the square (look for drift off the square) move the saw from stop to stop it's full movement to make sure it tracks correctly, make adjustments as necessarily to keep that blade against the square for the entire travel. If it is one of the older saws with no adjustment on the saw or tracking (ya they used to do that..lol), then your left with shimming the fence to get it aligned, much more tedious but doable. You bolt a sacrificial piece to the fence and use the shims at each bolt location on the low side to bring it to square.