Quick Foundation Question, 10 Points!?

So I’m going to be buying the Covergirl Naturluxe foundation. These are the shade choices.
http://www.google.com/imgres?num=10&um=1&hl=en&biw=1024&bih=653&tbm=isch&tbnid=Z_lW0Vh7YtMKgM:&imgrefurl=http://www.amazon.com/Covergirl-Natureluxe-Foundation-Alabaster-1-Ounce/dp/B0043OUJBE&docid=DfuGxlySumZsyM&imgurl=http://images.amazon.com/images/G/01/hpc/detail-page/shade-chart_covergirl_20101610_B0043OYFW8.gif&w=305&h=332&ei=oRBdT9CgHKnw0gGX1MW9Dw&zoom=1&iact=hc&vpx=100&vpy=133&dur=2&hovh=234&hovw=215&tx=110&ty=163&sig=116831358956696207673&sqi=2&page=1&tbnh=141&tbnw=130&start=0&ndsp=15&ved=1t:429,r:0,s:0
AND
http://www.covergirl.com/natureluxesilkfoundation
Now I was wondering which shades are meant for more cooler skintones and which ones are meant for more warm skin tones. or pink undertones or yellow. Thanks so much, 10 points to best answer! oh and how should i apply to get the best natural looking coverage/flawless skin? thanks!