Chess 960 castling

The FIDE laws, Guidelines II. Chess960 Rules, II.3 Chess960 castling rules say that from the following White to play position where none of the white pieces have moved

any of the following four moves are possible.

As opposed to normal chess, where only two are possible. Is this the way it's actually played?

I thought it probably wasn't. Presumably castling c side is possible only with the rook to the a side of the king and g side with the rook to the h side. Is that the way it's played? What rules are used if not FIDE?

Dear all,

Below is a screenshot of my game. I'd like to castle the king in d8 with the tower in e8, neither has moved since the beginning of the game, but it doesn't work ! Can you help me ? Thanks.

960 castling leaves your king and rook where they would be for normal castling. To castle with the rook on e8 would be kingside castling, so f8 and g8 must be empty. This is not the case, so you can't castle that way.