Intwenothor described pretty well the steps for the layered method and Jayvee's ESB (and ROTJ) paint thread is one of the best here on TDH.
The weathered/un-weathered colors are actually the same; in this case the caboose and the un-weathered caboose is the same color , but it means that the un-weathered caboose is a slightly lighter and cleaner red than the base color (see the example on the left upper mandible near the physical gash). At the back plate the reefer gray and the weathered reefer gray is the same color, but the weathered is darker, possibly the base color is painted on top of that color.