connected to modem wifi but no internet connection

So I have a vdsl2 p880 2t2r modem which works fine with a wired PPPoE connection. However, it looks like it also supports wireless WLAN, but although I can access the modem and activate wifi and connect to it successfully, I still can't get any connected device to reach the internet.

So I'm wondering what settings I should check -- and even if this p880 unit supports wifi internet access or if the wifi is only to access the unit itself (which seems unlikely because there are options on the modem setup pages that seem to apply only to setting up a wifi internet access point.)

Is there a manual for this p880 unit?