In Early Modern English, ye was the nominative(subject) plural of you. The whole conjugation looks like this:
Singular Subject: Thou
Singular Object: Thee
Plural Subject : Ye
Plural Object: You
In Standard English, "you," has replaced all other forms.
In the past you would say: "Did ye go to the store?" In Standard American English, you would say: "Did you (all) go to the store?"
Note: Many people think that ye = the, but this is incorrect! However, you will sometimes see it used that way. For example, a store might be named: Ye Olde Gift Shoppe (The Old Gift Shop).
While it is good to know these things because you will sometimes see them, it is best not to use them in conversation because, here in America at least, they sound funny. We only use these forms when we are joking (or playing Dungeons and Dragons or something).