Starting in the side mount (with your right knee against your opponents hip), if no submission holds become available you will want to move into the mount.
If your opponent has their knees up preventing the step over method, grab hold of their belt.
Slide your right knee onto your opponents stomach just above the belt.
Continue the knee drive until your knee is on the floor. Do not let go of the belt until your knee is firmly on the ground.
Let go of the belt and take up the mounted position.