Freestyle body rotation/getting power from the hips

First of all, I don't know if these concepts are directly related. But I finally got some coaching tips and realize that I am plowing through the water like I am swimming like I am stroking with my belly on a surfboard. I have learned to get the high elbow recovery and now I feel the rotation of my body, or at least the potential for it to rotate. So my question is, do I force my body to rotate more, or is this a natural consequence of doing other things correctly? I can especially feel it on my left/non-breathing side where I can force myself to over rotate beyond which I am doing. The power from the hips part, I was told I need to do that, but I have no idea how to execute it.