How to setup additional wifi SSIDs with mesh?

Hello.
I have two Convexa-S (S1300) connected with WIFI mesh.
Currently I have two Wifi networks (SSIDs) on them, one for Home use and another for Guest (configured using Admin panel for guest network).

I want to add an additional WIFI network (SSID), for use of some IOT devices at home.

How should I go about this, so that this new WIFI network will also be supported by the MESH (exist on main node and sub-node automatically) ?

I don’t see any way to add an additional WIFI netowrk (other than Guest) using the Admin Panel.
I an familiar with LUCI and Openwrt so I have no problem configuring it there. I just need some guidance how to do this so that MESH will be supported also.

Thanks…

You can ssh to the router and modify /etc/config/wireless, just copy the settings of guest wifi and create another one.