Create a design on paper by determining sound equipment you will need and where you want the workstation located. Consider computers, monitors, amps, mixers, keyboard controllers and any other equipment you will be using. Amp rack openings should be 19 1/8 inches to allow for rack rails and a slight margin of error. The keyboard surface (keyboard tray or table top) should be approximately 28 inches off the ground.
Measure and cut the pieces for the table top, keyboard tray, rack enclosures and any other pieces according to your design. Cut the wood with a table saw or have it milled at a lumberyard. Cut the table top 3 to 4 feet deep and as wide as needed. Cut the keyboard tray slightly wider and deeper than your keyboard or other controllers. Each rack enclosure will require two side pieces, one back piece and a base. Cut side pieces to be approximately 30 inches tall to allow a keyboard tray to attach below the table top. Cut back pieces to 19 1/8-by-6-inches and the base to 20 5/8-by-36-inches. After the wood is cut, sand all faces until smooth. Paint or stain all pieces to your preference and allow to dry.
Assemble rack enclosures. Use wood screws and L-brackets to attach side pieces to base. One at a time, place side pieces directly on top of the base and align to the outer edges. Insert three wood screws through the bottom of the base into the side pieces. Place one screw approximately 2 inches from each end and one in the direct center. Repeat for each side piece until each enclosure is constructed. Attach two evenly spaced L-brackets to each side of the enclosures using sheet metal screws to provide extra support.
Attach table top to rack enclosures. Use an electric drill with a one-quarter-inch bit and set drill stop at one-half-inch to drill openings for dowels on the table top and side pieces of rack enclosure. Drill two dowel holes approximately 2 inches from the front and back edges on the top plane of each of the four vertical rack enclosure pieces. Mark where these intersect with the table top and drill similar holes into the underside of the table top. Place a dowel in each hole of the enclosure pieces and secure with glue. Align dowels with table top holes and fit table top snugly onto rack enclosures.
Attach rack rails to the inside of the completed rack enclosures. Align a single rack rail vertically on the inside edge of each side piece and inset them slightly from the front of the opening. Use sheet metal screws every 2 to 3 inches to secure rack rails to rack enclosures.
Construct remaining parts of the workstation according to your design. Attach the wooden keyboard tray piece to tray guides with wood screws, and install guides to the workstation according to manufacturer's instructions. Construct shelves for computers or monitors as previously described with dowels and wood glue, and attach them directly to table or simply place on top with felt pads.