Reolink
Duo & Duo 2

This screenshot shows the main Settings page for the various Reolink Duo and Duo 2 camera models.
Your menu items may be different due to variations in firmware.

At the top of the Settings page, next to a picture of a Duo camera, it shows:

Click on the camera name to display the Device Info page

Information for each of the other options is listed below.  In some cases, a link is provided to see more details about the option.

When appropriate, an option is identified as CRITICAL or Important.  Please give these extra attention.

Network

Selecting your WiFi Network.  Once this is set during the initial camera setup, you probably don't need to do anything here.

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

Device Volume

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 ...

Push Notifications

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 ...

FTP Upload

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

Siren

You can ignore this. I don't know why this isn't located under the Advanced settings. It allows you to activate a siren sound from the camera every time it detects an event.

Share Camera

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.

Advanced

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.