If you haven't already, please setup the UniFi NVR and cameras using the instructions located here: How to Setup and Configure Unifi NVR for Unifi Cameras
The API key can only be generated via the NVR's Web UI. To access the UniFi NVR's web UI:
- Using a web browser, enter the NVR's IP (see Find Your NVR IP Address) into the address bar. You may see a security warning ("Your connection is not private") - this is normal for local access. Login using the Unifi account which you setup the NVR.
Once you are logged in, navigate to Settings > Control Plane > Integrations > Your API Keys > Enter a name > Create API Key > Copy the generated API key
Save the key somewhere safe, and/or send it to your mobile device. You will need to paste it into the Deep Sentinel App in the next step.
For more information and/or next steps, see How to Setup and Configure Unifi NVR for Unifi Cameras