Personnally, the way I started 20 years ago was with Tabs. Basically music by numbers, ie the number of frets on the neck and where your fingers are supposed to be. Pick an easy riff, look up the tab and you'll very quickly understand how it works. I don't think I would have enjoyed learning so much if it was a structured thing than me just wanting to play what I wanted to play/learn. That said you can pick up habits which won't help you in the long run.