When there are spaces between a rook and the king you can castle,
This is kingside castling, You have to move your king two spaces and the rook will move over automatically. It's the same for queenside.
KIESH2 (edit:sorry about the kingside castling diagram,when theres a space all you do is move the king over two spaces!)
I'm new here and I would like to know how you castle. Help me please.