How do I overlap songs?

Special Interest Groups Recording Techniques
1

Okay, so lets say i have three tracks that are different guitars to one song.
how do i put them together so they all just play at the same time???

2

Use the Time Shift tool to drag each track to where you want it.

http://manual.audacityteam.org/index.php?title=Audacity_Tracks_and_Clips#Time-shifting_clips

– Bill

3

no, i mean how do i put them together into one track??

4

You don’t need to. All tracks are automatically mixed into a single stereo file when you Export (or a mono file if all the tracks are centre panned mono track).
Audacity does not “Save” audio files - the “Save” function creates “Audacity Projects”. To make an audio file that can be played in other programs you use “Export”.