Playing my first 960 game right now and I can't castle. From what I've heard, castleing is still a thing in 960 and that's why the rooks must be on opposite sides of the king. What am I missing?
Yes, there is both short and long castling in 960 similar to regular chess.
Here is the full list of rules regarding castling: https://www.chess.com/terms/chess960#castling-in-chess960
In short, think of this way: In regular chess, White castles short which results in the King on g1 and the Rook on f1. When castling long, the King is on c1 and the Rook on d1. These are the same coordinates which the king and rook will end up on in 960 when castling "to the left" and "to the right".
It takes a few tries for it to really stick so keep playing games, and it will clear up very quickly 
Playing my first 960 game right now and I can't castle. From what I've heard, castleing is still a thing in 960 and that's why the rooks must be on opposite sides of the king. What am I missing?