Don’t worry, I come from MK too. Just going by using the PS3 controller, the button layout should be like this (i’m a 360 player but the buttons should be the same):
You have LP (Light Punch), MP (Medium Punch) and HP (Hard Punch, probably, i’m still new to this too).
Square = LP
Triangle = MP
R1 = HP
Then you have LK (Light Kick), MK (Medium Kick) and HK (Hard Kick):
X = LK
Circle = MK
R2 = HK
L1 = All 3 punch buttons
L2 = All 3 kick buttons
The other things you have areL
Focus Attack = MP + MK (Triangle + Circle)
Throw = LP + LK (X + Square)
So in essence:
1= LP
2 = MP
3 = LK
4 = MK
Then you have R1 and R2 for HP and HK.
If a command has 2 punch button, it dosen’t really matter which one’s you press as the same EX moves come out (EX moves are the same as EX moves in MK). So say you are doing a Hadouken which is QCF (Quarter Circle Forward) + Any Punch Button, you can instead press two punch buttons which makes the move have different properties and be generally better. In this instance, the Hadouken will become red and hit twice, so it can go through focus attacks and other, non EX projectiles.
Pressing all 3 punch buttons (or L1 in this case) is generally used to perform an Ultra. Ryu’s first Ultra is QCF x2 + All 3 punch buttons (L1). Ultra’s can use all three kicks too.
I hope this helps!