D-Link DSL-3590L User Manual page 123

Section 5 - Connecting to a Wireless Network
You will then be prompted to enter the network security key (Wi-Fi
password) for the wireless network. Enter the password into the box
and click Next.
If you wish to use Wi-Fi Protected Setup (WPS) to connect to the router,
you can also press the WPS button on your router during this step to
enable the WPS function.
When you have established a successful connection to a wireless network,
the word Connected will appear next to the name of the network to
which you are connected to.
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