Press Space to punch. Press E to throw fireballs . Press D or A to move. Press W to jump. Hold S and then press E to do the FLUDD attack. Hold W while in the air and press Space to do an upwards attack. Press Space while in the air to do a custom air attack. Hold S while in the air and press Space to do a downwards attack.
I kind of just copied the link test sprite (link here: http://scratch.mit.edu/projects/19360297/ ), but I changed a few scripts and changed the costumes. Credit to Spriters Resource for the Mario sprite looks (I couldn't find the person who made it), and also pixlejoint for the fireball (again, I couldn't find who made the sprite).