1. Plug in the adapter into a USB port of the PC. Turn the G Pro X Superlight mouse on. (And use a separate spare mouse, preferably not another G Pro X mouse to avoid confusion, to navigate the PC).
2. Launch " G Hub"
3. From the left-side menu, go to "Settings"
4. Select "Device Pairing Tool" under "SUPPORT"
5. Select "Pair Mouse"
6. Select "LIGHTSPEED MOUSE" for RECEIVER, and then "CONTINUE"
7. Select "PRO X SUPERLIGHT" for MOUSE (should say "Disconnected" underneath), and then "BEGIN PAIRING", which took me through the steps, including turning the mouse off and on at one point.
8. Pairing should finish and the mouse should begin working wirelessly!