D-Link AC3200 Ultra User Manual page 166

Section 5 - Applications
Connecting to your USB Storage Device from a Windows PC:
To access your files, right click your storage device and select Open or Map network drive. The drive's contents will be displayed in Windows Explorer.
If a login prompt appears, enter your DIR-890L's web configuration utility's username and password you created when you set up your router.
D-Link DIR-890L User Manual 161