Usually i think there's nothing better in order to learn a stroke than to look at very good players doing it. With the one-handed bh that's a little bit more difficult.
Pros will always have three things you should not copy in your backhand right away. You should not have supination at all at first. Just try to hit as far in front of you as you comfortably can, and hit the ball from below, this will give you enough spin for the beginning. Supination comes naturally as soon as you get comfortable and as a result more lose when hitting.
That also is the 2nd point. The oh-bh always looks very fluent and lose, but when first learning it you should try to keep a solid stance and also compact throughout your body. Add the flow when you're more used to the shot.
This is also true for body rotation. Pros will open up their waist when hitting the ball. As a beginner i recommend you to keep your body in the closed stance you approach the ball in, until after the ball is hit. This will make it much more easy to control.