Change length of transitions

I use iMovie 11.

In a Qigong tutorial I show 10 moves. I would like to lengthen the transition time between each move. 1) How do I do that?

2) Also, I show each move three times by repeating the clip of that move two more times. I don't use transitions between each time. Probably should, just have not yet. Is there a way to lengthen the time between each rep other than using a transtion? Any recommendations?

Would appreciate your comments.

BTW, I am beginning to like iMovie 11.