Use a 1/4 inch nut driver to remove the two screws securing the upper front bulkhead to the front of the chassis.

One 16.4 mm-long sheet metal screw

One 19.8 mm-long sheet metal screw

Use a 1/4 inch nut driver to remove the two 16.5 mm‑long sheet metal screws securing the top plastic portion to the upper front bulkhead.