Ableton LiveAt the left top of Ableton Live’s interface, click on the Plug-in Device Browser icon (third icon from the top). From the plug-ins list, double-click FabFilter/FabFilter Pro-Q 3, or drag it onto the track.
Add audio files on both the main track and the side chain track. You can simply drag audio files from a Finder/Explorer window onto a track. Select the main track and add Pro–C 2 in the first Insert effect slot. Open FabFilter Pro–C 2’s interface, enable Side chain expert mode and set Side Chain to Ext.