Next, carefully clean the receiving end of the buttons on the motherboard (shown on picture) with a cloth.

If the buttons are clearly damaged, then they need to be replaced.

Add the new ones in the form, with the correct button order. (The correct button order has the Triangle on the top, Square on the right, Circle on the left, and X on the bottom).

Be very careful! The buttons only go in one way. If you have trouble fitting them in, rotate them in their given spots until they fit in easily. Do NOT force them. Forcing the buttons in may cause damage.