I created this start frame for another video a while back, and don't remember all of the details of how I made it.

https://files.catbox.moe/grl9s4.png

I used Qwen Image Edit on a crude image first created using https://app.justsketch.me/, which provides a digital version of the old-fashioned posable wooden mannequins artists often use for human figure drawing.

This was much better that trying to verbally describe this pose, especially because AI models in general have an awful time understanding this particular kind of upright kneeling -- tell an AI image or video model you want a character to be kneeling, and it will almost always come out as kneeling and squatting at the same time, hardly ever understanding the idea of the upper part of the legs being vertical.