The Logic Board is the part that the keys hit and translates the signals to the phone.
Remove the back cover and the battery.
Remove the 4 screws using a T6 precision screwdriver.
Flip open the phone, and keep the back cover facing you.
Take the plastic opening tool and run it between the phone case and phone body to loosen the key pad while the phone is open.
Note: There are 2 clamps that lock it to the phone case (1 on each side).
Flip the phone over and lift straight up on the key pad to remove it.
Use the i Pod opening tool to remove the 2 ribbon wires (boxed in the photo) from the logic board.
If the parts are loose you can remove the black sim card reader and green vibrator before continuing, otherwise they may fall out.