Everything moves exactly as with FIDE chess, except that pawns at e2 and e7 are Royal and the Kings are non-royal.
Standard board.
The Pawns at e2 and e7 are Royal Pawns.
1. A Royal Pawn
can't move through check.
1b. A Royal Pawn
can't put itself into a circumstance which would allow it to be captured via en
passant. (That would be self-checking.)
2. In the unlikely event a royal pawn
reaches the eighth rank, that shall be a game ending move counting as a win.
3. A non-royal King can castle.
4. A Royal Pawn
can not castle but must move as any other pawn.