Once your device is connected to the extender's signal:

Might be http://v515.install or http://v515/install — but v515 isn’t a standard domain.

This guide will walk you through how to use this link to get your camera online and integrated with your security system. Before starting, ensure you have the following ready: ADC-V515 Camera and its included AC power adapter. A 2.4 GHz Wi-Fi network (the V515 does not support 5 GHz). An active Alarm.com account with a video service plan.

Some embedded devices (e.g., IP cameras, routers) use hostnames like v515 for upgrade URLs.