The first step would be to cut the ricordea/mushroom off at the stalk, detaching it from the rock. Use a piar of sharp scissors for this.
Since it is the same process for fragging mushrooms as it is for ricordea, I'll use a photo of a mushroom as an example.
The next steps are optional. You can leave it whole or cut into smaller pieces.
This photo shows how to cut into 2 frags.
Or if you wanted to cut into more than 2 frags:
For the best results try to get a piece of the mouth in each section that you cut.