Adding a camera surveillance system to home assist

I just purchased a home surveillance system for the first time and have multiple cameras installed and up and running. I’m just concerned about using a cloud service to remote view them so I haven’t connected to my local network or created an account for anything. Just changed the default password for now. Would it be possible to show how to add something like this to home assist?

Also just a little background. I have a Pi 3B that I was running retro PI on, but never really found myself using it after the first week or so. Do I need to do something special to remove any information stored on the SD card before downloading and installing Home Assist, or would Etcher take care of that automatically in the flashing process?

Thank you