The idea for the play mode is a better tool than video, as mentioned in my top main text. So while autoplay to the end is cool (when I fix the timing issue on more than a few steps), I don't see how that can be more useful than a manual controlled one for learning purpose if I have to choose only one for the play button. If I can fix the timing issue, the autoplay will likely get its own button.

Forgot to reply to "why can't click on step in steps viewer to skip". That's my original intention, but the effort to make that work well is too time consuming, so the step viewer is just that, a viewer.

My original thought on selecting other models to view is something like youtube. But I like the cleanliness of the current layout and not clutter it with next suggestions. I think clicking "folds" at the top is a fairly easy thing to do to find the next fold.