I did this for the 1st time last year and loved it. You eat first, and then go to the event. In order to ensure everyone who got the dinner package gets a seat, they begin a line to the left of the seating area and then they start seating at a designated time before the event.
Since we didn't know that last year, we walked all the way from Japan (where we had our dinner) to America, only to have to come all the way back to get in the line.
When I booked, I believe I got scheduled for dinner about 2 hours before the show and I almost felt rushed. Just because I had the dinner package did not mean I got sat immediately. That still works like a regular ADR so I put my name in and then waited 20 minutes before I was seated.
If you want to ensure that you have an up front or covered area seat, make sure you eat early so you have time to get in the line.