Getting your song up on YouTube is easy! Just go to your profile page and click on the song you want to upload. Click the YouTube icon (1). In the dialog that appears, you can preview your video before uploading. Click "Upload" and follow the publishing steps on YouTube :)
(1) Click on the waveform to show the sharing icons. Click the YouTube one.
(2) In the dialog you'll see and hear a preview of your song as it will appear on YouTube. Click Upload and follow the publishing steps on YouTube.