You can actually create audio files of your work, not just text files. This way you can play your song in your media player or incorporate it into other your projects for various DAWs. More excitingly, you can share it with the world through sites like SoundCloud and YouTube!
Exporting your BeepComp source is done by pressing the EXPORT button(or F12). The currently supported formats are: WAV, MP3 and OGG files. You just type in a file name with the extension for the format you desire and press the Export button. After you export your work, you can add fades and finishing touches of other kinds with audio editors like Audacity.
Note that by default your music won't be looped when exported.
If you want your export to be looped, specify the total number the song should play in succession with the command REPEAT=n in the global section. If you want your track to play through once and then fade out, write REPEAT=2 in the global section, load the exported file in an audio editor, and apply a fade-out around the middle of the file briefly after where the song repeats.
Well, that's it for the first tutorial!
Now what you can do to explore further is... go look in your userdata folder (the default folder when you first press the LOAD button). There are some example files and tutorial files there. Load some of these files and play... and change things around in those files to see what happens. This way, you'll learn many more exciting things you can do with BeepComp!
Also, the documentation has an extensive reference for all the commands you can use and the parameters you can play around with. Well, I promise you'll be kept busy for the next few days :)