A security notification may open after the installation begins. Use Touch ID or enter your password to allow the installation to continue.
You'll see a progress bar. Once the installation has completed you'll see a message in the dialog box that the installation was successful. Click Close to exit the box.
This driver application may open automatically following the successful install above.
If it does not, open LaunchPad, find CH34xVCPDriver Application, and open the App.
Click Install to install the driver.
Finally, quit the application. That's all there is to installing the WCH USB to serial driver for Mac OS X 11.0 and above!
If you are running the older supported version of Mac OS X 10.9 to 10.15, then you will need to restart your computer and follow the steps detailed on pages 3 an 4 in the PDF included in the zip folder.