Sensor Groups for Door contacts can be found here:
The group dictates how that sensor behaves. You would choose the group that best describes what action you expect from that gate sensor.
What is the use case?
Should it trigger an alarm, or just be used to notify when it opens/closes?
Sensor Input: Reed Switch indicates the sensor will use the internal reed switch with external magnet to track the opening/closing of the door, or gate in this case. Is that how you intend to use the device?