Once you have the PCB developed, Place the board artwork up in a tank of ferric chloride. An hour with no heat or bubbling is about the right amount of time, but check it periodically. When it is done, wash it off with water, then expose it to light again with no mask and strip off the resist with developer. Sand or cut off the excess baterial, but leave 1/4" on one side. With a 1/32" drill bit, drill out the holes. Also, drill a sequence of holes in the excess space as shown. We'll be using this to sew the regulator to the pouch in a future step.