You just move your king two squares to the right or left (depending if it is Queen or King side castle), and interface move the Rook automatically for you.
Castling

'click here' scoll down near to the end of the page till you see the heading 'castling' hope that help if not if me a buzz.
I'm very new to this site and as for now I'm just playing against the bot. But I can't figure out how to do castling.. any help?
Thx