How to do it without hurting myself?
Jump up, don't jump or push your board forward or backward. Don't jump with you toes, jump with the entire sole of your foot.
It's not just this trick you are eventually going to get hurt one way or another but just try to practice a lot and you can get the hang of it pretty fast
Of course you have to prevent it by buying some gear protection. Before you do the trick on a roll start by practice any section of the trick separately on flat. 1st the kick, 2nd the grab, 3rd the rotation of the deck, 4th the landing. Practice, practice! Massive longboards team
I always start something slow and then get faster as I get more comfortable doing the trick. Starting off stationary in the grass until you get the motions down helps too.
Umm... You need to accept the fact that your gonna hurt yourself at sometime. Another thing is is you might want to learn to fall correctly so you don’t majorly injure yourself.
You will at some point get hurt longboarding. Get some protective gear and take some time to learn how to fall properly. I think Braille Skateboarding has a good video on how to fall properly.
get some elastic bands for your wrist, it will help A LOT
Sorry is impossible