Reolink
Duo, Duo 2, Duo 3

Selecting your WiFi Network.  Once this is set during the initial camera setup, you probably don't need to do anything here.
This does not apply for PoE cameras.

Important.  All things related to what you see on live and recorded video. More details ...

Optional.  Control the volume for the speaker (used for you talking to someone and for the alert siren).

Important.  Control the Detection Zone, Sensitivity, and Object Size. More details ...

Critical.  Control what is recorded to the data card in the camera (or, optionally, to the cloud).  More details ...

Optional. It controls which events/alerts appear on your smartphone.  There are separate settings (see Email Alerts below) for which events/alerts are sent to AwareNet.  Many camera owners choose to leave this turned off. 

CRITICAL!  This option controls which events/alerts are sent to AwareNet.  It is critical to the success of AwareNet to set this correctly. There are separate settings for which events/alerts are displayed on your smartphone. More details ...

You can ignore this. It is used only by "techies" that want to store their video clips on an separate storage server. 

This feature is not typically used.  However, it can be useful as an additional deterrent, but may annoy nearby neighbors.  Instead of triggering a default siren sound from the camera according to a schedule, it can play a 5 second recording / announcement (e.g. "Alert, your activity is subject to real-time monitoring and response").

Optional.  Displays  the UID (unique camera id) and a QR code which is a digital representation of the UID. 
To give someone access to your camera, you must give them either the UID or the QR code, plus a userid and a password.

Optional.  Manage userids & passwords, set the date/time, control sound recording, the infrared lights, and the spotlight.

Although not required, it is often helpful to have audio recorded with the video clips so please turn on Record Audio.

The other settings here can be left as-is.