All the chord charts I'm finding just have black dots on the frets, they don't tell you which fingers to place where. For instance the charts I got from bootcamp. D7, do I bar the second fret with my index finger and put my middle finger on E string 3rd fret? Bb? Do I use four fingers or bar the E and A? I'll probably hear just form them however feels right. But if there is a correct way to form them I'd prefer to be doing it. Thanks.