Here's some extra resources on posture and positioning. Don't get too hung up on it. Main thing is to get playing and practicing. You won't be perfect but the more you play and keep micro adjusting what I talk about in the video, the more comfortable you will become.

My video on on youtube all about 'notes on the piano'

https://www.yamaha.com/en/musical_instrument_guide/piano/play/play002.html

Top Ten Tips for Good Piano Posture