Where to book restaurants on board?

When we booked our upcoming cruise NCL offered 2 free dinners at the pay restaurants on board. When we get on the ship where do we go to make our reservations for these since I know we can't do that ahead of time?

Will they have our information documented somewhere?

You can book restaurant reservations on board by calling (I think the phone number is 050...at least it is on many ships), or going to the restaurant reservation desk(s)...typically one at the side of the guest services desk, and another is in the buffet during breakfast and lunch hours. (There may be differences in location by ship.)

Any restaurant host can help during hours.

we usually decide on the night where we want to eat although some itineraries places might get booked up

On the newer ships (we saw it on the Getaway), you can book in you room from your TV screen.

On the newer ships (we saw it on the Getaway), you can book in you room from your TV screen.

Yes. And they call this a TV Dinner. :D

On newer ships if you download the free iconcierge app to your smartphone or tablet you can book. There are also tv touchscreens throughout the ship that you can use to make reservations and browse the current freestyle dailies.