Exporting your remixes

Once you're done your remix, and you've ended it with an End Remix entity (looks like two vertical bars, found in Other > Special Entities), you can export it to a sound file.
Click the export button on the toolbar:

And you'll be sent to the Export Remix screen.

There are a lot of options here.
The green bar allows you to trim how much of the remix to export. Left click will set the beginning, right click will set the end, pressing R will reset the bar to the entire remix, and holding SHIFT while clicking will round to the nearest beat.

Once you're set, click the bottom button to choose a file to export to.
Accepted file types are: mp3, ogg, flac, wav.