Hold a curtain bracket about 2 inches away from the top corners of the preferred window, standing on a step stool if necessary.
Mark the wall through the curtain bracket openings using a pencil.
Drill the curtain brackets to the wall, directly over the marks.
Rest a curtain rod on the bracket hooks.
Drape your fabric of choice over the curtain rod in a way that matches your preferred style. The more fabric you have, the more elaborate a design you can create by looping the fabric over the curtain rod with as much or as little slack as you wish. While you can use any cut of fabric, rectangular cuts work very well for this sort of decor.