Connect different wlans

Hello,

I'm a beginner openwrt user and I'm looking for suggestions about how to connect two different wifi lans together.

Currently I have a netgear router with dual band wlans, but I'd like to reuse this device only to give wifi access to a number of iot devices without changing anything, just moving the router in another room for coverage purposes.

I don't have possibilities to reach the netgear via ethernet cable.

From this new location, I should setup a wifi bridge - I think - that connects the old router to a new modem/router (fritzbox 7530).

Each device, the old netgear and the new fritzbox, have separate lans with different SSIDs and different networks, one is in 10.20.0.0/24 and the other will probably be in 192.168.something.

How can I accomplish this configuration ?

What I have to look for ?