Begin by getting confident and comfortable with your back bridge, starting with the wall and then trying it on the floor. Without the wall, lift 1 leg up about 4 to 6 in (10 to 15 cm) off the floor and do 10 small kicks, so you can get comfortable with the movement. Then, switch to the left leg and kick a little bit higher and further. Continue practicing these leg kicks every day until you're comfortable with the full kick over on a walkover.