The adapter needed:
USB 3.1 Gen 2 type C to USB 3.0
USB 3.1 Gen 2 Type A to USB C adaptors and cables are hard to find but if you are using the Type A port on your Mac it is USB 3.0 so any USB A to USB C converter or cable will do. Personally I am trying to get rid of any cables with type A connections so my new cables are type C on both ends and I use a Type Adaptor like
this or
this. By the way, in case you have any lying around unused, an old Thunderbolt 3 cable will work as well or better than a USB C to C cable using these adaptors.