Chris Sawyer wrote:
but screwed up the landing and I hurt my ankle. What could I be doing wrong?
Possibly not controlling your feet in landing? It's a common error - you have to learn not to allow your feet to thump down at the end of your fall - instead allow your entire body to absorb the force of the landing, preferably as smoothly as possible
The way to practice this is to keep your feet tucked up but relaxed, use your stomach muscles to control your legs, and allow your feet to land in a natural position rather than tense or curled.
Take it slow and steady, as the others have said, and you'll get there!