Combine two tracks

[TheNewNumber2]

I figured out -- it was very simple -- how to combine two tracks, but the problem is at the point I want them combined, it simply stops the first cue and then goes to the second. I am wanting to combine the two tracks so they are playing at the same time for the 10 or so seconds that would cross onto each other, the way I want it edited.

How do I achieve this? I don't even know what to call it.

[makeitloud]

I wanted to do the same thing, but I also couldn't figure a way to do it. I just had to time the cut perfectly to sound smooth... I also had to increase the volume of the beginning and end of the two tracks because the two songs fade in and out; however, that didn't turn out very smoothly, but it's not very noticeable... It would be nice to be able to do it the way turntables do it, but if that's already possible, I don't know how. I'm new to this program.

EDIT:
OK, I am not certain how you did it, but thanks to your question, I realized I did it all wrong when I did it.

So, here is what I did and now I can have both songs over lapping each other to make a smooth transition from one song to the next.

First, I open one track with Audacity. Then I go to "Project" and select "Import Audio..." From there, I select the file I want to combine. Now, both tracks can play at the same time, but they will both start at the same time. We don't want this. So the thing to do is this... First, select the time that you want the track to start by using the selection tool. Just click in that time, but you must select it in the area of the song you want to move (you can select an area that is outside of the song if necessary). After you have made that marker, go back to "Project" and select "Align Tracks", then select "Align with Selection Start". Now the two tracks will play in a smooth motion! I hope this helps, and I hope I made sense!!!

[TheNewNumber2]

I discovered a little trick, though I am sure there is an easier way to do it.

Have one of the parts you want to combine, opened in Audacity. Then have the second part ready, but not opened in Audacity. Go to: Project > Import Audio..., then select the second track. It will open below the current one. Hold down shift and select both, then File > Import As WAV, or what every type you are doing. It will combine the two if you have them set to where you want them combined, so that may mean sliding one part around on it's time scale. Worked for me, but it says when I do it that it will split both into two stereo channels ,so I am not sure the tracks will mix right together and play back at a precise way for someone looking to have it 100% the same.