Sorry I couldn't make it all the way through your video. What I did watch looks like skidded turns and that you're ruddering your back leg to turn. Turn initiation should be taking place at your front foot and begining of the effective edge. At this point it looks like the other issue is your lack of speed. It is more challenging to initiate at the front with out speed. With increased speed turns will become easier to initiate and you will be able to increase your edge angle. In the video your edge angle is pretty flat to the surface when turning, this makes it difficult to turn and increases edge catch.
Posture wise you're pretty upright. You'll want to bend your knees more and use your toe and heel pressure to turn.