I want to build mesh-like network in two floors of a house - single SSID for all devices and for 2.4 and 5 band.
Main ISP router has Ethernet cables on each floor.
- device A on second floor (wired to router)
- device B on first floor (wired to router)
- device C extending WiFi from device B on the first floor in difficult to reach rooms
What are the proper configurations for each of A, B and C devices?
MT1300 is not made for home mesh, you should consider Velica (GL-B2200): GL-B2200 / Velica - GL.iNet
If you can get wired connection for each router, you can use the same SSID and password for all the MT1300 routers, they might act like a mesh network to your end devices.
If you have wiring points to all three rooms then just run your three MT-1300 in access point mode off your ISP router, make sure they’re set to different bands (1,6,11) and name them all the same SSID
Or (I’m not quite sure about your layout), 2 X AP (Room A and B) and 1 X repeater (repeat device C from device B)