Well, hard to give you advice when we cant see your mistakes
you should post a video, then it will be easier
but anyways, first step is to get good at the first touch
You shall train combos like htw - matw, matw - matw, atw-htw-htw-atw-atw (inside atws of course), and yeah multiple atws
when your first touch is good enough it is just a matter of time before you will do it, you just have to figure out the technique on your own
but yeah the jumping part, you should do it when you've reached the 1/4 of the latw
if u jump smaller you need to be faster, and opposite with a taller jump (if you find it hard to be fast enough, then practice the movement in the air without the ball)
now it is up to you, peace and good luck!