I have a hard time finding videos of round penning (on Youtube) that I think are good ones.
But, for having the horse turn toward you, you must learn to "draw" the horse. People spend so much time driving the horse in the round pen that they forget to use a draw to bring the horse back to them. You will want to practice making the horse move his feet away from you, and at various speeds, and haveing the horse stop and turn back to face you, and if you invite him, come walking toward you.
When he stops and turns toward you, back away a couple of steps to "draw" himtoward you. Then, the tricky part is to be able to have him turn enough to offer you the other side of his body,(even if it's only his cheek) so that you can then push that side away and out onto the ring. that's the change of direction to the inside. And yes, a video would be best.
But you can at least do some work both driving him and drawing him.
And don't wear him out to round pen play. It's all good and well to do it if there's an issue, or to "play" now and then, but it can be stressful and can sour the horse if you do it a lot.