Simply put, it's a diagram that lays out the relationship between every musical note, key, three-note chord and scale and thereby suggests where your melody or chord sequence might 'go next'.

For example, if you've ever gotten a chance to look at one of the CMA Awards trophies up close, you'll notice a tiny circle of musical notes inscribed on its surface.

Thus Coltrane’s circle shows those same 12 semitones and their notations (flat or sharp). The outer ring portrays the hexatonic or whole-tone scale of the note Do, and the inner ring portrays ...

Don't be afraid. The circle of fifths looks confusing but it's only ever here to help. And a basic understanding of what it's trying to tell you could lead you down a whole new creative superhighway.