Yes, Dave is right. In Ableton, you will need to find your keyboard/controller and set it up. Next, on some MIDI track in Ableton turn on record and check to see if you are getting a MIDI signal (hit one of the keys and it will register a visual signal). That is just t check for a MIDI signal, if you want the sounds from the Novation only, then MIDI has no roll here. Simply plug in the outputs to the Scarlet, select those channels in Ableton as analog and record.
Now, if you want to record the MIDI signals to what you played on the Novation, then you will record the MIDI signals, then output that back to the Synth, and then record the analog signal back to the DAW. That way if you need to edit any of the notes you can on the MIDI, the send that signal back to the synth so that the sounds can come back to the analog track.
It sounds confusing, but really it is simple, you have MIDI, which is just a digital data stream, and a sound module on the keyboard. The MIDI is sent to the sound module and is converted to an analog sound. In your DAW, you can record both the data signal and the analog, but since they are two different data types, you will need two tracks. One for MIDI and one for analog.
I am not sure how to make it clearer without going into much deeper detail.