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.
Twist your body sideways and switch your knees so that your left knee is now on your opponents hip.
If your opponent brings their knees up to prevent you taking the mount, simply clear them out the way with your right hand.
With your right hand still on your opponents legs, step over it. Now prepare to take the mounted position.
Push with your left elbow, hand or leg and place your right knee on the ground to finish in the mount.