Install the mounting plates to hold the curtain rod over the window, placing them within an inch of the top of the window and positioning the plates within 1 inch of the left and right top edges of the window.
Cut two pieces of hook-and-loop tape that match the total height of the drapes. Separate the hook half and the loop half of each piece and set aside both loop halves momentarily. Remove the adhesive backing from the hook halves and place them onto the wall running down the window immediately under the points where the curtain rod returns mount over the window. Remove the adhesive backing from the loop halves and place them onto the back side edges of the drapes.
Put the blackout drapes on the curtain rod, sliding them over the length of the rod evenly so they cover it completely.
Hang the blackout drapes by setting the curtain rod into the mounting plates. Position the drapes so they cover both returns and sit flush against the wall.
Press the sides of the drapes onto the wall to affix the two sides of the hook-and-loop tape.
Mount the cornice above the window, over the curtain rod. Because the cornice has top, front and side edges, it blocks light from entering along the top edge of the window.