To answer some queries on Intelli-Burn Dodge..
Select the "Burn & Dodge" layer and set brush opacity to say 5%..
To dodge(brighten) part of the image, choose foreground colour white and paint over those parts..
Conversly, to burn(darken), use foreground colour black..
Tip: Use "D" to set default color (Black) and "X" to swap colours..
To reverse the effect of burning & dodging.. fill the whole layer with 50% gray..
Or use brush with 50% gray (R128,G128,B128) to brush over those parts to restore..