Step 9: Preparing for the power strip
Put the power strip in for a dry fit to figure out where the cord will go. Then mark it and cut it out with a square saw. Be sure to round the end to accomodate for the roundness of the cord. I used a 1/2" Forstner bit for that.
Also, since you've got like 14 screws sticking into the box, it might be a good idea to cover those. I used some pink insulating foam leftover from when we remodeled some years back. Just cut them to size and glue them down (wood glue or super glue works fine).