There is no specific video on this, but the knees will pop when it goes from straight to bend too fast (or vice versa, ie from straight to bent).
The cause can be many things, which you will get better at discovering.
It could be that the heel is raising too much, or it could be because the foot is too far from the hip. Or the hips are too high from the ground etc.
To be able to fix this, you need to develop your eye to recognise the cause and how to avoid it.
(sorry there is no magic answer – but seeing the pop is the first step)
