You have to think in binary.
The dip-switch at address 0 has all the switches off
Switch 1 on makes it address 1
Switch 2 on and switch 1 off makes it address 2
Switches 1 and 2 on make it address 3.
Switch 8 must be OFF for all boards except the one WIRED the furthest away from the P-ROC board. This one must have switch 8 turned on.
The PD-LED boards are a bit different. All switches OFF means it is address 8, and they go up from there. The PD-LED boards must be wired in the same physical string as the PDB-16's.
-Hans