In the beginning, I would recommend using a chair that does not move. You are going to try to make a step with your knees. This will be difficult at the beginning.

1. Stand on your knees, close to the chair at 90°.
2. Lift the chair and set it back down half a foot forward, keeping your hands on the chair.

3. Shift your weight on the opposite knee, feeling that the body weight is on that knee.
4. Once you feel the weight, lift your other knee slightly forward. You may drag in the beginning, but try to keep your knee off of the floor and prevent it from dragging.

Use your hands that are on the chair for balance. You may lean a bit on the chair until your muscles get stronger (avoid leaning on the chair too much and stand at 90°). Once this becomes easy, increase your difficulty depending on the items that you possess. The next step will be using something with wheels, for example, you may push a walker forward half a foot or lift the walker half a foot. Repeat what you did in the beginning. Once this has become easy, you may try an exercise ball which you can roll half a foot or pick up the exercise ball and place it half a foot in front of you.

The final step is to kneel 90° without anything for support. At first, try to make the steps ridiculously small and make them larger until this is easily accomplished. For extra fun, hold some weights in your hands to make it more difficult for your body to adjust, just like in real life.