On the top surface of your project box, measure in one inch from one of the shorter edges. Next, make two marks that are 1/3 and 2/3 of the way between the edges of the shorter distance. These will be for the potentiometers

Measure in one inch from the opposite side of the front of the case. Make another mark that is 1/2 way between the two edges. This hole is for the stomp switch.

On the side of the case make two marks for audio jacks where you would like, so long as they won't interfere with any of the other parts that will be installed.

Following the same logic as the audio jack marks, make one last mark for a toggle power switch.