How to merge two subnets Asus brt-ac828, Xiaomi Mesh Router Suits, ASUS XG-U2008?

Question

Computer networks

Good evening.
Given:
1. Asus brt-ac828 router
2. Xiaomi Mesh Router Suits
3. ASUS XG-U2008
Internet access via Asus.
WiFi via Xiaomi. Which is connected to Asus
LAN clients via ASUS XG-U2008 to an Asus router.
Problem.
Xiaomi creates its own subnet.
How to set up routing, taking into account the fact that xiaomi has in the admin panel .... as if there are no such settings. Yes, the device is new.
Thank you!

Answer 1

You need to set xiaomi to access point mode so that it relays the addresses issued by the asus and there will be a single network.