Using the cardboard, align the right angle with the edge of the window frame Place the rod hanger on the cardboard where you’d like to install it. Using a pencil, mark through the rod holder screw holes onto the cardboard. Poke holes in the cardboard. Align the cardboard on the window frame and make a mark on the walkthrough the holes. Flip the cardboard and repeat on the other side of the window. Drill pilot holes in all marked areas on wall. Align the rod holder with the holes and screw to wall. Repeat on other side of window frame. Using the rod, extend to desired length. Tighten rod holders on rod.