It can take all year to set up interfaces that span multiple controllers via the GUI. A good trick is to do this in Notepad and just change the values for each interface, once they are built for a single controller, just chance the IP address and paste to the others! If you cant remember the commands do one interface in CLI using Tab, if you cant do it using Tab, learn!
Also, only use lower case for inteface names, if you use upper case, they will show in GUI as lower case, but not map to WLAN's correctly!
config interface create guest 11
config interface address dynamic-interface guest 10.10.11.15 255.255.255.0 10.10.11.1
config interface dhcp dynamic-interface guest primary 10.10.210.6
config interface port guest 1