On Windows 10, 8.1 and 8 systems, the driver is built in. Just plug in the USB side of the adapter. Windows will setup the driver for the first time.
On Windows 7 systems with Windows Update enabled, just leave the network cable connected to a different network adapter (so Windows Update can be reached) or enabling Wifi and just plug in the USB side of the adapter. Windows will look for the best driver.
Drivers for many platforms (including Windows 7 or older, Mac, Linux, Windows CE, etc.) are available for download. The complete list of drivers and supported platforms for the AX88772 chip in the Plugable USB2-E100 is available on the ASIX AX88772 driver download page.
Or use the drivers from the included CD-ROM. Please download and update to the latest driver after connecting to the Internet.