Robin, don't be intimidated! Sketches are just kind of guidelines for the layout - you use whatever colors/patterns/embellishments etc you want, generally arranged as per the sketch. The different shades/shapes etc. are just for differentiation - so if a sketch shows a big flower, YOUR interpretation could be something else in that spot! Some folks follow the sketches exactly, some use them as a starting point for their creation and often the end result is a bit different. We just want you to join in and have fun!
The greatest challenge in life is discovering who you are. The second greatest is being happy with what you find.