If you have the benefit of a bench vise, open the jaws open far enough to allow the tire to drop into the vise. Hold the wheel up about 1/2" above the jaws and tighten the vise to close any clearance of the tire. Then twist the wheel to break the beads from the wheel. Remove the wheel/tire from the vise and proceed with removal.
p.s. Do not to any maintenance to your bike simply to save money. Any thing you do to your bike , do it with supervision or confidence you are doing it correctly and (I will use this overused word) SAFELY. You have all winter to play with your bike. You can also read all the "how to", GOOGLE, and hang out with your buddies, watch and ask ?s. Then fiddle with your bike with an understanding of what your end objective should be.