If you are not doing closed headjoint start with it closed, right palm covers the open side of the head joint. This is easier to make a sound on than open.

I have a big picture of flute embouchure that I use from Band Directors Talk Shop that I blow up on the board and use as a model. (https://banddirectorstalkshop.com/flute-embouchure/)

Kids look in their mirror and match their face with the one of the board.

I'd also invest in some pneumo pros to use if you don't have any.