The PCB, or Printed Circuit Board, is where all the tester bits get placed and assembled. There are a couple of different options to consider here.
The first option would be to order the PCB through a manufacturer like OSH Park.
Just send them the files and they make and send you the PCB(s).
For the purposes of this guide we will be showing off mainly this method.
Another option is use a desktop milling machine such as the Bantam Tools desktop CNC.
The Arduino proto shield is a great option if you don't have the right files to send to a PCB manufacturer or you don't have access to a milling machine.
For mounting standoffs with this method, you will have to drill holes where you'd like the standoffs to go.