Before configuration, try to reset to factory default.
Open Browser go to default ip address 192.168.2.1
Input User & Password. default user is "super" and password is "sp-admin".
go to wireless tab.
Select channel according to regulations. input the ssid, security (optional ). then select root bridge.
and select non-Root Bridge to other device. then update settings. save. reboot.
on non-Root Bridge ip address is 192.168.2.254. change ip address later. if you have many device.