is 那 actually used for "that" or did my book lie to me lol

so i was looking at this kanji 那 in my vocabulary list and the book says it means "what" or "that" or something. but wait i thought what was 何 and that was あれ?? why is there a whole kanji for this if nobody uses it? or is it like a secret grammar thing? i saw it in 那覇 for okinawa but that doesnt mean "what" does it? am i dumb or is my textbook just completely wrong because im so lost right now