recording new mono tracks with an mp3 track

I import a mp3 audio track.
Can I add two or three horns parts to it and mix it to a new stereo file?

I added a new mono track but I can’t select it to record.
When I hit the red record button a new stereo track appears.

Can someone point me in the right direction, please.
Thank you

ps … Can I record the original track plus overdubs in real time to a digital recorder from the computer’s audio out port?

audacity 2.1.2
windows 7
.exe installer

To record a new track, you don’t need to create the track first. Just start recording and Audacity will automatically create a new track.

It may or may not be possible, depending largely on the sound card, but why would you want to do that? Audacity is a digital recorder, so what’s the point in complicating the issue and trying to stream in real time, via an analog interface, to another recorder?

The current version of Audacity is 2.1.3 (available here:

Thanks for the info.
How do I mix all the tracks down to one file? I would have mp3 and wav files in the mix.
I would like to record three mono tracks of trombone and pan them left center and right.
So far, all I can record on are new stereo tracks.

Have a read through the “Getting Started” guide:
I think that will help you to get started.