Hands to feet is a common starting point and an important basic to learn. Here are some simple starting point skills for both the top and the base to get comfortable with working together. Really simple stuff, I know but basics, basics, basics just like in any gymnastics discipline.
So some basic stepping up and down.
Some squat jumps ups. Some stationary squats for balance checking.
Some transferring of weight from side to side more difficult for the base.
Thank you to the my Portuguese friends. All photos from the FIG Level 3 Coaching Academy in Lisbon.