[noun] + をください [noun] + を + [number + counter] + ください
をください asks for a thing: "please give me ~", "~, please". The thing you want goes in front of it, marked by を. ください is the request form of くださる, the polite verb for someone giving something to you.
The number and its counter come after を, straight before ください. English puts the number in front of the noun; in a shop or a restaurant, Japanese puts it here.
をください asks for an object. To ask someone to do something, put the verb in the て-form and add ください (〜~てください).