Applies to SL MKIII
To set the SL MKIII up with Ableton Live 11 please connect and power your SL MKIII and then open Ableton. The setup is the same as this article, with the inclusion of MPE for the pads to use Polyphonic Aftertouch.
Then go to the Preferences (Options > Preferences on Windows, Ableton Live > Preferences on macOS) and go to the Link/Tempo/MIDI tab and match the settings below:
Note that enabling MPE for input port means that all MIDI channels are in use, so it's not possible to set a track to discretely respond to one MIDI channel. You may wish to disable it if not using Polyphonic Aftertouch data from the pads.