Hold the curtain rod in the desired location above the window on the drywall. Have a helper place a level on the rod and adjust the rod until the air bubble in the chamber of the level is between the two vertical lines.
Mark a line on the wall where the brackets need to be installed with a pencil. Lower the rod and set it aside. Hold the brackets up against the wall where you drew the lines and mark the screw holes on the wall with a pencil.
Install a drill bit into an electric drill that is the same size as the wall anchors being used. The anchors should be the same size as the bracket screws.
Grasp the trigger part of the electric drill with your dominant hand and place your other hand under the front of the drill. Hold the drill at a 90-degree angle to the wall's surface the entire time you are drilling the holes. Use a moderate amount of forward pressure to guide the drill bit into the wall over each mark you made designating the location for the bracket screws. Back out the drill while it is still spinning to avoid damaging the edges of the holes.
Insert a plastic wall anchor into each hole and tap them gently with a hammer to make them flush with the wall's surface.
Align the bracket holes with the wall anchors and secure the screws using the electric drill with a driver bit installed. Install the curtain rod onto the brackets