This is the absolute best advice I can give you, but it won’t help if you don’t do it. The various slave positions you might use don’t depend just on knowing how to kneel a certain way. It’s also important that you emote them well. So go somewhere you have complete privacy and nadu.
Close your eyes. How do you feel? Does it tickle your back when you move your head and your hair switches over your back? How do your thighs feel against the backs of your palms?
Open your eyes. Look around. How does it feel to be kneeling, for your body to be so much smaller and vulnerable than normal?
Look into a mirror while kneeling, if possible. What might others see when they look at you kneeling?
Rush back to your computer and write down as much as you can remember, then do the same with the next position. Also make note of how you settle into the various positions, and how you move out of them.
This gives you an understanding of what it feels like and what you look like when using these positions.
I’ll keep adding to this page, so please check back often.