Shoulder Buttons are the buttons located on the back (from standard handling viewpoint) of the controller. On the PlayStation 2 controller, there are 4 shoulder buttons - designated L1, L2, R1 and R2.
Random History: The modern "shoulder" button concept first came from Nintendo, in the Super Nintendo Entertainment System controller, released roughly between 1990-1993. The SNES controller and it's shoulder buttons influenced every controller released by any company for all future systems.
Chat with our AI personalities
The D-pad buttons is basically the directionall buttons on the ps2 controller... basically the up,down,left,right buttons.
analog sticks
The d-pad is the set of directional buttons on the left side of the controller.
Both of the shoulder buttons and the triggers are white on a standard XBox360 controller. The Start and Select buttons are also white on the standard controller.
That means to push left on the directional pad, which is on the left side of the controller with four buttons in the cardinal directions.