Depending on your restrictions - the menus in the restaurant are great with their identifiers (icons)..dairy, nuts, gluten, sugar, etc....
I have quite a few restrictions and after checking in when we stop at the table that is set up near where you check in (believe it is the restaurant manager) they have a list (assume based on the preferences you check) of passengers with restrictions..so good place to start. Also recommend if you find a waiter/table you like the first night - stick with that table (if you can). This way the waiter and his team know your restrictions and can accommodate them.
When in doubt - always ask your server - better safe then not