John,
Sorry the diagram was confusing. I'll try to take it step by step.
The power supply has two wires on its output - red (positive) and black (negative).
Black goes straight to terminal 2 on the PID, where it is joined by 3 other wires - one heater wire (either, heaters dont have polarity), the black fan wire, and a wire to the motor terminal (the one with the red dot near it)
Red goes to the center pin of both switches.
One of the outside pins of one of the switches goes to terminal 1 on the PID.
One of the outside pins of the other switch goes to the red fan wire, as well as the other motor terminal.
Connect a jumper from terminals 1 to 4 of the PID.
Connect the other heater wire to terminal 3 of the PID.
So:
Terminal 1 of the PID has 2 wires under it
Terminal 2 of the PID has 4 wires under it
Terminals 3 and 4 each have 1 wire under them
The first switch has 2 wires on the center terminal, one wire on one of the outside terminals (either is ok)
The second switch has 1 wire on the center terminal, two wires on one of the outside terminals (either is ok)
Hope that helps!