These phrases are known as idioms and can't be directly translated word for word very well. "Here you go" is something you might say as you hand somebody something they asked for or needed. A waiter might say this as he hands the customer his food, or if somebody needed a tool and you had one you would say this as you offered your tool to them. There you go is the same but the only difference is here versus there. So the item you are helping or giving might be farther away. If somebody rented a bike from you, you might point to the bike and say "there you go"