What is LuCI
LuCI is the web user interface of OpenWrt.
To access LuCI, at the left side of web Admin Panel -> More Settings -> Advanced.
For some models, the LuCI isn't preinstalled, click Install LuCI to continue.

After installed.

Click the 192.168.8.1/cgi-bin/luci will go to LuCI login page.

Note: The username is root. The password is same as the one that you use to access the web Admin Panel.