If you need to delete one of your tracks, just head to your My Uploads page. To do that, click your profile icon at the top of the screen, then "My Uploads."
On that page, click the pencil icon on the song you'd like to delete.
When you do that, a pop-up will appear where you'll see a "Delete song" button at the bottom.
When you click that, an additional confirmation will appear. Once you click "Yes" your track will be fully deleted.