Leg Movement of Ballet

For the next step for this project, we try to comprehend the topic and try to implement it by doing it. Unfortunately, I wasn't prepared so I decided to utilize video of others that showing the material for the latest topic (basic leg movement).
Here I include the video that I made:

I think the easiest move out of these 5 basic movements are the first and the second. It is like a stand up straight and put both of the heels together. Slide a bit wider and voila that is the second position.

While for the difficult ones which are the forth and fifth position I don’t feel comfortable at all although both of the movements are in sequence. I feel like twisting my feet into unnatural position that makes me want to either tilt or stop doing it. This makes me wonder how could a ballerina stand to stand like that?