Plug the collated ground wires into the Arduino Ground pin, and plug the other jumper wires into the correct I/O pins: Toggle switch - 0 Pilot LED - 1 TTL output - 2 Rotary switch 1 (ontimes) - 3, 4, 5, 6, 7 Rotary switch 2 (frequency) - 8, 9, 10, 11,...