Cut a 2-by-2-inch square of Velcro for each pedal and one for the power supply. Cut two thin strips of Velcro to fit across the width of the inside of the pedal board lid.
Glue the square pieces of Velcro to the base of each of your effects pedals and the power supply. It's essential to use a power supply unit if you plan on leaving your pedals plugged in. Leaving the cables connected will drain the batteries, even with the pedals turned off. The power supply unit should have multiple power cables for powering individual pedals.
Open the pedal board case so that the lid lies flat on the ground. Glue the thin Velcro strips on the inside of the pedal board case lid, close enough so that the Velcro square on the pedal base attaches to both.
Unclip the lid from the case and lay it flat on the floor so it becomes a flat board. Lay the power supply unit on the top right of so that the Velcro strips hold it in place.
Fit the tuner to the left of the power supply. The tuner should be the first pedal in the signal chain. This enables it to get as accurate a reading without interference from the other pedals.
Attach a small patch lead to the output of the tuner pedal. Fit the next pedal in your sequence to the board, to the left of the tuner. Connect each pedal with a patch lead. Connect an instrument cable to the "Output" jack of the final pedal. Connect a second instrument cable to the input of the tuner.
Connect the power supply cables to the "DC In" on each pedal. Turn the power supply unit on to power the pedals.