Is the engine out?
If yes, put it on an engine stand (they can be rented). Turn it over and unbolt the connecting rods. Use a ridge reamer to clean up the ridge at the top of the cylinders. A ridge reamer can be borrowed from Autozone. Once the ridge is removed and the connecting rods are unbolted you drive the pistons (with connecting rods attached) out threw the top of the cylinder. Now you can clean up the pistons, install the new rings, clean up the cylinder walls and re-install the pistons/rods. Pay REAL CLOSE attention to driving the pistons back into place. YOU DO NOT WANT TO TOUCH THAT BEARING SURFACE ON THE CRANK with the connecting rods bolts. I always slip a rubber hose over them and let the hose straddle the crank. This is very important. Make sure you install new crank/rod brgs too. They are pretty cheap. Come back with questions as necessary.