Where Should I Place SwitchBot Hub Mini/Hub Plus in My Home?

It's up to you.

You may set up Hub Mini/Plus on your table, or attach it to a wall with the supplied magnet, as long as it faces to the controlled appliance's IR receiver (LED side).

If possible, try to set up your Hub Mini within a clear line of sight of your WiFi router.

Note: Building materials and metal objects located between your WiFi router and Hub Mini or between your Hub Mini and mobile devices may slow the connection.