You have your opponent in the guard and will apply an arm-bar to their right arm.
Take your opponents right arm to the right and secure it just above the elbow with your right hand as shown.
Place your left hand on your opponents left shoulder with your arm under their chin. Now pull your opponent down slightly.
Uncross your legs (if using the closed guard) and put your right foot on the ground. Put all your weight on your right foot and left shoulder. Now swing your hips out to the right to create the space required for the next part of the technique.
Place your left foot on your opponent right hip. Now put all your weight on your left foot and right shoulder. Swing your hips out to the left so that you are nearly sideways on to your opponent.
Now swing your left leg under your opponents neck. If they try to put their head down to prevent you from doing this, simply push their chin up with your left forearm. To apply the arm-bar, keep your opponents arm pinned to your chest and raise your hips. Also try to squeeze your knees together slightly for a more solid hold.
As you apply the arm-bar, your opponent manages to pull their arm out.
To apply the Omoplata you must ensure that your opponents left arm is next to your right hip. Now twist anti-clockwise on your back and put your left foot on the ground.
Continue to twist on your back and take your right foot over your opponents left shoulder. Now take your left leg to the left and grab hold of the back of your opponents belt with your right hand.
To apply the lock simply come up on your right foot pushing your hips forward. Since you have hold of your opponents belt they will find it difficult to roll forwards and escape the lock.