Thank you for sharing this video, Chaz. That's a really good introduction to meditation, full of sensible advice from a seasoned meditation master. Too many people jump in, overexert themselves, and then just drop it. It does not have to be this way. Meditation does not have to be perfect -- as YM Rinpoche says, just a little bit at a time, but methodically, works well and adds up.
The Tibetan-style practice allows for relaxed sitting and nobody will be shocked if you wriggle a bit. I, too, sit on a chair sometimes. Also, the zafu does not work for many Westerners and maybe a rectangular cushion might be better.