By default, the drivers for the USB modem are included in Windows 8, 8.1 and 10. When you plug the adapter into your Windows computer system, wait a few minutes while the driver is installed. When the driver is installed, the USB modem appears under Modems in Device Manager.
To open Device Manager, press the Windows key + X and select Device Manager.
If the driver installation is not successfully installed, you can manually install the driver by completing the instructions in the following FAQ: http://www.startech.com/faq/lsi_install_windows_v78.