Measure the height and width of the window bench and shelving areas (Image 1). For the shelves, measure the material on the sides of the unit and the shelves (Image 2).
Using a piece of scrap wood as a guide, cut out the shelves using a circular saw. Wear a mask if you're working with medium density fiberboard.
Lay out the uprights and measure where you want the shelves to sit on the unit.
Pre-drill the vertical sides and the shelves for the screws.
Assemble the shelving unit using wood glue and tighten the cap screws.
Use a hand sander to smooth any rough edges. Put your bookshelves aside.
Measure the area of the bench frame. Cut 2x4 boards with a miter saw to create the frame.
Remove any existing baseboard trim. Install the lengths along the wall using 2-1/2-inch screws (Image 1). Lay out the shorter pieces of 2x4 boards to create the outline of the frame (Image 2).
Measure the frame and use a circular saw to cut pieces of plywood to create the skin (Image 1). Attach the cover with wood screws and work your way around the frame (Image 2).
Put the top piece in position, then measure one top storage door.
Cut the door with a circular saw and handsaw (Image 1). Using 1/2-inch wood screws, attach a piano hinge to the door and bench top (Image 2).
Attach the trim around the bench with glue and finishing nails (Image 1). Finish it off with paint and crown molding (Image 2).