do you want to automate panning? go to the track in the edit window and click where you see the word waveform on the left of the track. A menu will pop up that says blocks waveform volume panning etc, choose panning. Then you'll see a straight line in the middle of the waveform, this represents panning and you can draw it in any way you want.
You can also record it in real time. In the mix window, in the track you'll see a button that says "auto", click that and choose write. Now when you play back, anything you do to the panning will be recorded. Then you can fine tune it with the way i described above.
Sorry this was kind of long.