The pistons are connected to the rods, which are connected to the crankshaft. You need to unbolt the rods from the crankshaft, and then pull the pistons out the top. DO NOT PULL THEM OUT THROUGH THE BOTTOM, they will get stuck and will be very difficult to get out.
im assuming the engine is in the car? you will either have to remove the engine, OR i was thinking of trying to do it in car myself, idk if this will work though, you will have to remove the oil pan, and then the bolts that hold the crankshaft in place, I think its called the cradle? i dont remember.
Also do you have precise measuring equipment to verify the piston to cylinder wall clearance isnt excessive? Feeler guages. bore guage, micrometer? you need to see if the cylinder is christmas tree'd or if its the same all the way down
Do you know how to check the new piston ring end gap?