Hey - so yes that is the same thing that Bela does!! Very submissive I love you... so I can see Coco trying to step her foot up on your hand.. however your hand is always quite high when she does this - at one point you tried lifting the hand to get her to shift weight - which when there is confidence.. great - good that method works, but for now you're rushing and making it too difficult. Secondly, I see her mouthing you - this is ok, as long as they are EXTREMELY gentle about it... I say 'no biting' and Bela stays very light with it. You're moving a bit quick and rough to me, so try slowing down, that will also reduce the excitement and make the mouthing less aggressive in turn.
So far as the step up goes... when she's dropping her wings like that level your hand out more flat (horizontal) towards her breast and at the front of her legs, and say 'step up'... put slight forward pressure (towards her with your hand) lightly and see what happens.. go slow... the foot coming up is great! I'm not trying to criticize you here.. just give some pointers... If you do get her to step up.. just leave it at that... let her stand there quietly, maybe offer a treat, but don't go forcing to move her or pet her yet... get it going more down pat before you start taking her away. It's great especially that she's doing this in her cage by the looks of things! Goodluck