Answer:
In order to do a roundoff backhandspring back layout, you have to have a good tuck, like she said, and after you have a tuck, try doing a back pike. From that, try to open your hips. Make sure you set high enough. Then, once you have the set right, you have to bring your arms down in the middle of it. Bring them to your thighs. Then, out of a backhandspring, you have to dump your shoulders. Throw them backwards and there you go, you have a back layout! Good luck and have fun!