I use to have a lot of trouble too once. I started with doing them on my knees first and went up from there. Doing weights to build your chest like dumbell/bench press and flies will also help. Keep at it, it gets easier as you get stronger

Thank you ! I'll try weights and keep at doing them on my knees until I manage full ones ^.^

Sounds good. It took me time but I got it eventually. You will get there

Thank you I'll try that too !