Measure the width of your window and add two inches to your measurement. Cut two dowel rods to this measurement. Cut your fabric the same width as the window.
Sew a sleeve, just large enough to hold the dowel rod, into the top edge of your fabric. Place a dowel rod through the sleeve, with one inch protruding from each end. Position the rod over the window and attach the ends to the wall with your brackets, but do not tighten completely.
Place the decorative rods along the sides of the windows so they are parallel to each other. Position them to your desired awning slope and window covering -- this aspect is a matter of personal taste. Place the second dowel rod onto the ends of the decorative rods.
Drape the fabric over the end and mark the leading edge of the fabric. Remove the awning, cut the fabric to length and sew a sleeve into the bottom edge of the awning. Place the second dowel rod through the sleeve.
Reattach the awning and secure the brackets to the wall. Affix the bottom to the ends of the decorative rods.