Are you saying that you cannot read music, but you can write it? That's the first that I've ever heard that. Anyway, if you can understand what a chord is, and how to make chords, then you should understand the "BbEbG"s. That just simply tells you what to play, in other words, what keys make up each chord. Some write it like that, others write it as the chord name, for that one it'd be "Eb", since it's an Eb major chord.
If this is your area of ignorance, then you'll probably want to go to
www.looknohands.com and study the scales and chord construction there. This will help you with the above. If you're not ignorant in that area, then maybe you just worded your post incorrectly, or need more theory help.
Hope this helps....
