If you set the MnM keyboard to send midi (under global settings -> control out 1, the settings for sequencer, arp and keyboard can be found. Set keyboard to “Int+Out”) Ableton Live will receive midi from the trig keys.
Check Live’s setting if “Track”, and “Remote” are activated for the MnM midi in port.
Don’t forget to arm the track you want to play from the trig keys.
If you want to use the MnM as a controller for Live, use the MnM midi sequencer.
Under global settings -> midi seq you can set midi channels and midi ccs for the midi sequencer. Check if you want to change anything (conflicts with other gear)
Then enable midi mapping in Live, highlight a parameter in Live and turn a knob (CC1-CC4) on the MnM. Trig keys and notes from the midi sequencer should also work.