Place a camera, a monitor and an improvised keyboard (for interacting with the camera system) on your map.

Create a RenderTarget for the camera and create a material by right-clicking on the RenderTarget.

Once you have done this, you can now select the camera and give it the RenderTarget.

Now select the keyboard and click on the plus sign of the CCTV camera in the CCTV settings. Select the camera that you have placed in your map.

The same with the monitors.

Now you can insert the material of the respective camera into the CCTV Camera Lens Mats, exactly in the order in which you inserted the cameras.