This guide provides everything you need to know about finding, downloading, and installing the for Windows. What is the Gaintech USB 2.0 Auto Sharing Switch?
If you have the driver files (downloaded or copied from another source) but no Setup.exe file, you can install them manually: gaintech usb 2.0 auto sharing switch driver download
Check the box your switch came in. There is likely a small disc. This guide provides everything you need to know