Instead of the "User" credentials from the AP bottom label, try the "ISP" login uid=super, pw=sp-admin from an HTTP session. In the AP WebUI, from Configure::
Radio 2.4G or Radio 5G, you will see tabs across the top with Common and 8
individual WLANs that can be setup with unique authentication methods, from
Open Auth, to a WPA2-AES PSK (passphrase) that you can provide to your WiFi
users upon arrival, if this is what you seek. Individual username/password type
of authentication involving a RADIUS server (802.1x) is a little more involved.