What I check is the camera is getting video to the BNC ends by plugging each one into a monitor. Some folk don't have the monitor and can't test their setup. If so you have to decide if you need to call in a tech to sort it out.
Also, most of those cards have settings for NTSC, PAL and more. I am not offering to detail all the settings. You as the CCTV system builder have to know this area.