Open Ableton Live on your computer and begin a new session or open a previous session by clicking the "File" tab in the upper-left part of the screen. Click "New Live Set" for a new session or "Open Live Set" or "Open recent Set" for a session you have already worked on.
Click the "Insert" or "Create" tab located near the "File" and "Edit" tabs at the upper-left corner of the screen. The name of this tab depends on which version of Ableton you are using.
Click on "Insert New Audio Track" when the menu appears if you wish to record instruments or vocals. Click on "Insert New MIDI Track" if you have a MIDI controller that you will record with. Ableton Live's tracks default to the stereo setting having both a left and a right input. The "1/2" external input signal that will be shown upon creating a track is a visual representation that your single recording has two inputs.
Record any instrument or vocals onto the track. To record in Ableton Live, first click your track's "Arm" button, which is located in the upper-right corner of your track and looks like a standard "Record" symbol. Next, click the "Global Record" button, which also looks like a standard "Record" symbol and is located near the center of the toolbar in the upper part of the screen. Finally, press the spacebar on your keyboard or the "Play" button, which is next to the "Global Record" button, to begin recording.
Experiment with panning once you have recorded a track. While some very creative effects can be added to any track, stereo recording's major purpose is panning, or moving, the sound signal closer to one of the two outputs so that it sounds more present in one speaker than in the other. To do this, click and drag the "Pan" knobs located in the mixer to the left or right.