Almost all IP surveillance cameras and DVRs support RTSP video stream, which is a network protocol in order for the Proactive software to access the live video feed. RTSP is the abbreviation of real time streaming protocol, it's a network control system designed for use in entertainment and communications systems to control streaming media servers.
Camera and DVR manufacturers generally provide an RTSP URL string, allowing a user or application to access the live video stream. When installing the Proactive software, it is required that this information be available, with the associated surveillance product you are using. This information can be found in the documentation provided by the manufacturer, or through support resources on the manufacturers website.
Once you have gathered this information, connecting your live camera feed to the Proactive software is completed, and the one time initial process is finalized.
If you also can't locate the RTSP URL easily, you may need to contact the manufacturer directly to make sure your surveillance product is supported with this protocol.