Create a thread if you want to show anything you've recorded, it doesn't matter if it's just 1 song or if it's 14 songs compiled into an album.
You can add a cover, make your own booklet pictures, or anything you want to make your thread look like an actual release.
Good sites to upload your songs would be:
· Streaming site
· Video-sharing site
· File-sharing site
Unless it's an original song made by you, don't forget to mention the original artist of the song you've recorded!