If you hope to pull the heads and replace the piston rings, you’re into an engine rebuild. I strongly urge you to invest in a manufacturer’s shop manual and study it before attempting this. It isn’t as simple as just unbolting the heads, disconnecting the connecting rods from the crankshaft, and sliding the pistons up. There are a lot of complications involved including but not limited to the ignition system, the valvetrains, dropping whatever needs to be dropped to remove the oil pan (there are often crossmembers etc. under the car) removing the oil pump, and on and on. I should also add that if the engine is that worn you should be pulling it and replacing the crankshaft bearings too. That involves learning how to measure clearances and on and on and on.
And you’ll need to invest in a whole lot of new tools.
The pros make it look easy, but trying to do rings yourself for a first timer is major work. If you have the time, the cash, the inclination, and the desire, go for it. If you’re hoping to get your engine to stop seeping oil through the valvecover gasket and think this is an inexpensive way to do so, you may want to rethink the project.
Just my opinion. Take it or leave it.