Cut the maple down to size. The top TV section will consist of two long 3/4-inch maple sides, two shelves (one of which will have a shorter depth), and a 1/4-inch maple back. The bottom sections will consist of two small adjacent cubbies that have three 3/4-inch maple shelves and a 1/4-inch maple back.
Use the table saw to create a rabbet cut along one edge of the two long pieces, which will serve as the sides of the TV section. This will allow the back to fit snugly inside the frame once it's assembled.
Mark a row of three biscuits on two long pieces along the two edges and another row 6-inches below one of these rows. On the connecting pieces, make three markings on the thin corresponding edges. Use the biscuit joiner to create holes at each of the markings.
Place biscuits and glue inside the three rows on the long pieces. Attach the shallower perpendicular board to the biscuit holes that are 6-inches below the edge and one of the other boards to the bottom biscuit holes. Attach the second long piece to sandwich in perpendicular to the two shelves.
Place clamps onto the unit to hold the pieces together while the glue dries. Flip the unit over and add more clamps so each of the pieces hold together securely. Use a square to make sure the pieces are squared-up before proceeding to the next step.
Flip the unit to its true bottom and make sure everything is nice and tight. Place glue around the rabbet cut along the back edge and slide the 1/4-inch maple back into place with the better side facing in, since it will be visible. Hammer it into place with a mallet for a better fit. Staple around the back edge with a pneumatic stapler for good measure.
Create two bottom cabinets-in-one for the upper cabinet to rest on. Cut the pieces down to size and create a rabbet cut on one side of the longer pieces where the back will slide in.
Attach the three shelves to the cabinets with biscuits and glue. The bottom shelf should rest a few inches above the bottom of the unit to create legs. Staple the 1/4-inch maple backing into place.
Measure and cut down walnut trim with a chop saw. Cut a mitered edge on pieces that connect at the corners. Glue the walnut trim along each of the exposed edges, including the bottom edge along the two sides, and nail the trim into place.
Secure the top section to the bottom cubby section with 1-1/4 inch screws. Screw in from the bottom so the screw heads aren't visible.