Basically, I recall the menu being something like:

Option 1:
- Speed + Cadence Sensor signal
​​​​​​- Power Meter signal

Option 2:
- Speed Sensor signal
- Power Meter + Cadence Sensor signal

Option 3:
- Speed Sensor signal
- Cadence Sensor signal
- Power Meter signal


Each sensor has a unique ANT+ ID that is stored in the head unit and when stored, the head unit listens for those particular signals and records the data they transmit.

Cool fact: Speed sensors can be used as Cadence sensors and vice-versa. They are basic reed switches and don’t carry any extra data like Power Meter sensors.