If you are using USB2 cameras from ZWO, they must be flashed with the -compatible firmware in order to be used with StellarMate.
Download the ASI Cameras Firmware Upgrade Tool for your OS and flash the camera with the -compatible firmware. For example, if you camera is ASI120MM, then flash the camera with this file: ASI120MM-compatible.iic
This is not required for USB3 cameras.
However, when using USB3 camera with a built-in USB hub (e.g. ASI385), then such camera must be connected to USB 2.0 ports (Not USB 3.0). Otherwise, StellarMate would not be able to detect any cameras or filter wheels connected to the camera built-in Hub. If you are using an external hub (e.g. Pegasus Astro Power Box) then ensure you are connected to the USB 2/3 combined ports.