Step 1: Pairing.
Like most Aqara stuff, you need to extract the zigbee ID from the Hub catchall
From the example below, the zigbee ID you need is A8B2.
catchall: 0104 0000 01 01 0100 00 A8B2 00 04 115F 0A 01 01FF42296410016510006E20016F20000121E40C0328
Step 2: Assign the Aqara DTH to the newly created device
Step 3: Tie the 2nd input to a virtual switch handler. You can reuse the smartapp from my kudled DTH post
Note: The state of the buttons for the 2 gang switch will NEVER be able to be in sync. This is because smartthings masks the endpoint end when it returns the on/off status. Hence the DH will never know the on/off returned is for which button.
But you can certainly use it to explicitly send ON or OFF commands in conjunction with smartapps or other automations.