How do I select just one audio channel in Final Cut Pro X?

I know this has been asked and answered somewehre... and I'm pretty sure the answer is simple. But I don't have hour's to search the net.

And the FCPX "Help" feature just ****** me off....

I recorded voice on channel 2 and shotgun nat.sound on channel 1.

I only want the voice track (channel 2) to playback in stereo.

I have already edited the video so I don't want to re-import the raw video to seperate out just the channel 2 voice track.

How do I select just one audio channel in the timeline, then pan it so it plays back in both the L and R channel?

Also, some of the audio was recorded with a air conditioner running in the background. Any suggestions on best audio filers to remove or lessen it?

Thanks, Barry