Follow the instructions in the README file. Note that on newer versions of macOS (Big Sur and later), you may need to allow the driver in because it is a third-party kernel extension.
Click the button. A "Driver install success!" popup should appear. Plug in the HW-417. hw-417-v1.2 driver
This usually means a driver signature issue. Try downloading the latest version from the WCH website linked above. Follow the instructions in the README file