A number of Novation products work as control surfaces within Ableton. This means the controls on the device can be used to access various functions in Ableton, as specified by their control script.
While the mappings cover a large number of functions, you may want to edit the behaviour to suit your needs.
To do this, you will first need to connect your controller, open Ableton Live and got to the Link/MIDI preferences screen (Ableton>Preferences on a Mac, Options > Preferences on Windows) and make sure "Remote" is enabled for the port used for DAW control (InControl, MIDIIN2, DAW port, etc). This can will be the one selected in the top half of the screen:
You can see here the InControl is used for the Launchkey MK2, so that has the Remote set to on.
The DAW (MIDIIN2 on Windows) port has remote enabled for the Launchkey Mini Mk3.
Once this is set up, press MIDI in the top right in Ableton:
Then click the control you want to change in Ableton, for example, arrangement record:
Then press or move the control on the hardware you which to assign to that control in Ableton Live, for example, a pad:
If possible, you may want to customise the pad you use to be a Toggle when using controls like this, so that the record will stay on when the button is released. This can be done with Components for our MK3 products (Launchkey MK3, Launchpad X, Launchpad Pro MK3, etc).
Note: Ableton Live stores MIDI mappings per set and so if you wish to keep this mapping its advisable to set this up in a blank session and then go to the File Folder preferences to set it as your default set (the one you'll see every time you open Ableton.