Daniel C, great question! In my experience sitting just behind the sharp points of the buttock bones is the way to go. 

Thank you, Nathan…the balance poses were challenges, but used the chair to assist. I know as I continue this amazing challenge I will get stronger. You remind me of my favorite teacher, Bryan. He was meticulous with instruction ( like you -love it!) and it’s helped my asanas. Namaste   

Brenda S! Sounds like you are making great progress. The chair is an excellent idea for assistance! As you continue (and maybe even review lessons where you had extra challenges) you will see the improvement in your balance 💪