Siemens 315 series I/0 Module Help

I am putting together my first Siemens unit on my desk to learn more about this family of PLCs. I have a CPU315 2PN/DP—1 Input Module (321-1BL00-0AA0)—1 Output Module (322-1BF01-0AA0) and a power supply. While assembling the unit I noticed an ivory looking rotary switch (I think) in each module prior to applying the terminating segment. 1 on the input module and 2 on the output module. Can someone offer me some information on how these need to be set if any. I am an Allen Bradley user and have been to some elementary Siemens classes. I have never assembled a Siemens Processor from scratch.

Any help is appreciated
Thanks

The rotary looking "thingy" in the back of the card is only a mechanical safety so you can’t accidentally swap two different cards (e.g. a digital in and a digital out). This knob has no connection to the electronics inside the card.

Thinks

I appreciate your quick response. Thanks