Door curtains are usually sheer cased curtains, affixed at both their top and bottom to the door. The sheer fabric transmits light, but provides privacy. Special screws are required to install curtain mounting hardware to metal doors, but whether you are installing curtains on wood or metal doors, it is a simple task.
Slide the curtain casings onto the upper and lower curtain rods. Hold the upper rod against the door to help you decide where, on the door, you want to place the curtain.
Mark the position of the bracket for the upper curtain rod above and slightly lateral to the door light (window in the door). Measure and mark the corresponding position of the opposite bracket. Using a reference mark, hold the bracket in position and mark the screw holes on the door by passing the tip of the pencil through the screw holes in the bracket. Remove the bracket.
Drill pilot holes in the door, at the levels of the pencil marks. Replace the brackets and screw securely into place. If affixing brackets to a metal door, use self-tapping sheet-metal screws, which do not require pilot holes.
Hang the curtain from the upper brackets on the door. Mark the positions of the lower brackets on the door, 1/4-inch lower than the level of the rod. This will compensate for stretching of the curtain and keep it taut. Take the curtain down. Drill pilot holes and screw the brackets into place.
Place the ends of the curtain rods onto the brackets and evenly distribute the top and bottom of the fabric across the rods.