D-Link DSL-3590L User Manual page 136

Section 5 - Connecting to a Wireless Network
3. The Wireless Network Connection box will appear. Enter the WPA-
PSK Wi-Fi password and click Connect.
It may take 20-30 seconds to connect to the wireless network. If the
connection fails, please verify that the WPA-PSK settings are correct. The
Wi-Fi password must be exactly the same as on the wireless router.
D-Link DSL-3590L User Manual 132