To use this digital microscope on a USB-C MacBook:
Plug into USB-C port (be sure the USB to USB-C adapter is attached)
Open Photo Booth on the Mac
From the "Camera" menu at the top of the screen, choose "USB 2.0 UVC PC Camera"
Unscrew the lens cap, position the microscope and use the focus ring to focus
This can also be used on an Android phone. See instruction manual for details