I always get one end up out of the groove with a scribe and just go around the piston and the ring is off and over the top.

To put the new one on - I start one end down the side and more or less thread the ring around the piston and it snaps in place.

You need to clean out the piston ring groove with the old ring before installing the new ring.

There is a pin in the ring groove opposite the exhaust port where the ends of the ring go.

Orient the ring so the tapered end of the groove fits on each side of the pin.