Answer:
Its easy realy all you do is just bounce lightly and then het presto......... ur doin it!!
ok.... Proffecional trampolinest here. It depends how good you would like to be. if you would just like to know basics just go around google and find tutorials and stuff. that will work for a while but the best option is to go to a club. they will be able to train you better than watching videos will ever. if you want to be proffecional like me club is the only option. the main thing about trampolining to remember that, unless you are being stupid, its not that hard to do some moves, it just takes courage. there are a few exceptions eg double and triple summersaults. if you would like more info or help with anything inperticular, feel free to contact me =) hope this helps