Pretty easy really. Best disconnect battery or fuse to avoid horn honking when you ground horn wire. Release the two sprung screws retaining horn ring from behind wheel and remove horn ring. Pull out horn ground wire button and spring a bit. While you have the ring off, undo the three horn ring screws and remove ring. Check out the rubber "squeeze" ring, it may need renewing. Ron Kwas has a great article on horn referb at sw-em.com.
Important!...MARK the splines with a scratch, punch or paint to locate the alignment for the refit or you will lose the centering of the wheel when driving straight.
Grip wheel and undo center nut of wheel. Sometimes the wheel comes loose at this point. If not...
Plant feet on floor and slide body up seat back and grip wheel at 8 o'clock and 4 o'clock right where the wheel arms connect to rim with the arm tips between your fingers. That is, you want to pull on the very end points of the arms, not the rim away from the arms. This takes the stress off of the wheel and avoids breaking the plastic between arm and rim. Pull back hard and alternate pull from side to side. The wheel should come off the splines.
Bracing against the seat should help protect you from sudden release of the wheel. You can use a steering wheel puller if you can get one, it's usually the "H" bar with two bolts type that bears against the center tube but I have used the brute force approach with success.
Good luck.