Measure your computer monitor and compare it to the space in the TV armoire. Adjust the removable shelf above the space to create enough room for the computer monitor. Remove the shelf, raise the metal clips that hold the shelf in the vertical tracks, then replace the shelf.
Turn the armoire enough so you have access to the back. Mark a space at the bottom of the TV platform, about 2 inches from any side. Use a hole saw to cut a 2-inch hole through the back of the armoire. This is where the computer cords will exit the armoire to plug into electrical outlets. Drill one more hole in the back of the armoire in the underneath cupboards to let printer cords pass through.
Install an underdesk keyboard drawer on the underside of the TV platform. Screw in mounting brackets on the underside of the platform, insert the keyboard drawer into the tracks and push it in and out to ensure it glides smoothly. Follow the manufacturer's instructions for specific details on installation.
Set the printer inside the bottom cupboard and run the cables out the hole in the back. Stack printer paper, ink cartridges and other office supplies in the cupboard as well.
Maximize the storage space inside the armoire by putting wall-mounted file baskets on the inside of the side walls. Place baskets and containers on shelves to hold office supplies.