The connection method is as follows.
1. Log in the tablet and mobile phone to the same Xiaomi account, and turn on Bluetooth. If it is used for the first time, keep WIFI on and connected to the Internet.
2. When using the application on the mobile phone, a relay icon will appear on the right side of the Dock bar on the tablet desktop, which means that the connection between the devices has been successfully established.
That's how an iPhone and a Xiaomi tablet connect.