Screw the two elbow fittings into the ends of one of the 36-inch pipes. Aim the open ends down. This is the top of your garment rack.
Screw the two 48-inch pipes into the open ends of the elbow fittings.
Screw the four-way fittings into the bottoms of the two 48-inch pipes.
Attach the other 36-inch pipe to the inward-facing threads of the four-way fitting, creating a cross bar to support your vertical hanging rack.
Attach the 12-inch pipes to the four remaining ends of the four-way fittings, so they stick out perpendicular to the long standing legs of the vertical garment rack.
Stand the entire vertical garment rack up so it's resting on the 12-inch pipes (the "feet").