HOW DO YOU MAKE MORE TOP SPIN ON TWO HANDED BACKHAND?

Producing more spin on Two Handed Backhand is done by two motions,
with lifting left arm over the right and with left and right wrist mechanism.

What are the wrists doing exactly? Let’s say you are right handed.

Before the hit, left wrist is in back and down position and with forehand
semi western grip. Right hand has continental grip and because of left hand,
the wrist is in palmar flexion position. Simply by “pumping” i.e. pushing with
the right grip down, head of the racket will go up, as well as left arm, and
you will brush the ball from down going up. Depending how vertical you go – the
ball will have more spin.
Left elbow bends and goes up and usually points forward.
Additional spin you can create if you work more with your knees.