You have your opponent in the guard. Grab their collar with your right hand (fingers inside, thumb outside), and grab their right elbow with your left hand.
Uncross your feet (if using the closed guard) and put your right foot on the ground. Put your weight on your right foot and left shoulder. Now lift your hips up and take them to the right. This creates the space required between you and your opponent for the rest of the technique.
Lay your left leg on the ground next to your opponents right knee and bring your right knee across your opponents stomach.
Here you can see how your right leg should be positioned.
Now in one flowing movement straighten your right knee and scissor your legs, sweeping your opponent. Be sure to also pull your shoulders back, dragging your opponents right arm towards you.
In the same flowing movement, take up the mounted position. You will have your opponents right arm controlled, possibly for numerous arm-locks.