Irish has a very different way of expressing "want" and "have" than English. To say that someone wants something is to say that is from them. To say that they have it is to say that it is at them. To say "I want food" you would say "Tá bia uaim" or literally "food is from me" (and to make things more complicated, ó + mé = uaim. You will just have to memorize the Irish prepositional pronouns.) To say I have food it's "Tá bia agam" or literally "food is at me." Likewise, "you want food" is "tá bia uait" and "you have food" is "tá bia agat." Keep practicing and you'll figure it out.