Cut the plastic from the shell, aligned with red markers.

Use a cutter to cut the big pieces of plastic.

Use the cutter again to cut some plastic from the shell. This is required for the LCD to fit properly.

Only cut the plastic that sticks out! It's possible that the red markers are not 100% accurate. (For models with a motherboard serial number beginning with 1, there is normally no need to cut the plastic on the right side).

First things first, there are 2 GBA models. 32 pin motherboards and 40 pin motherboards, before you order anything, make sure which model you have. The GBA's starting with a 0 is a 40 pin, if it start with a 1 it's a 32 pin. Please advise Google if you are not sure which model you have.