Nutritional Labels - what do you look at first?

It is so confusing. How the heck do  you know which one to do? I try to look at fat, sugars and protein. If it is high in fat , I wont get it. The same for sugar. Which is right? HELP

ingredients first off to see if it has milk in it (allergy to milk proteins) then protein, is it worthy then fat, as a DS fat is my friend last calories does it fit in with my daily total