In this part of the game we will create the look of your game. First we will get your character and then we will add the platforms. It can be static (not moving) or animated. Search things like "Mario jumping" or "Sonic jumping Gif".
Upload your character as a costume under the hitbox then resize the hitbox so that it is about the same size as your character (make sure everything is centered).
Add this ONE code block to the code you already have.
Create this section of code.
And add it into your forever loop, here.
Finally to adjust the code for the number of costumes you have you need to divide 32 by the number of jumping costumes, round up and put that number here:
For example in my Mega Man game, Mega Man has 7 costumes so 32/7=4.57 Rounded up is 5.