Mark the center location where you want to add an access hole in your desk.
Set the point of a nail on the mark you’ve drawn on the desk. Tap the nail lightly with a hammer to create a shallow indent. Do not drive the nail deep into the wood.
Apply the appropriate hole saw to the drill. Lock the saw down tightly. Set the saw’s center bit into the shallow hole you have tapped with the nail, to help center the saw.
Drill the hole through the most visible side of the desk to the least visible side, to hide any flaws that may appear when the saw emerges on the other side. Cut completely through the wood, and remove the drill.
Wet your rag, and wipe around the newly drilled hole. Bind any loose wires with wire ties, and tuck away the wires so they’re no longer visible.