Double-click the Cubase icon on your desktop to launch it. Click "Devices," then "Device Setup." Click on "VST Audio System."
Click the drop-down menu next to "ASIO driver." Select the ASIO driver for your sound card. If no specialized driver for your sound card appears in the list, select the "Generic Low Latency ASIO Driver."
Click on the entry for your sound card's ASIO driver in the list on the left-hand side of the "Device Setup" window. Click "Release Driver when Application is in Background" if you want to be able to use a second audio program while you're running Cubase.
Click "Control Panel" to open the configuration page for your ASIO device. Adjust the settings as needed, then click "OK." Click "OK" to close the "Device Setup" window and apply the changes.