Tummy time on gym ball (lower limb hold) ('Baby development' Lifting head, prone, on stability ball)

Kneel on the floor holding your baby with the gym ball in front of you.
Lie your baby onto their front over the ball.
Support them around their hips, pelvis or thighs depending on their requirement.
Roll your baby forwards, away from you.
They should try to lift their head up.
Placing a mirror in front may help to facilitate this.
Then bring them back towards you.
Repeat this movement