^^^^^What he said!! ^^^^^^I wish someone would have given me such a great explanation last year when I decided to dive into MBN without a clue!
The only thing I want to add is if it is possible, go to a contest to observe an on site judging for yourself (be courteous of course).. You know, see the set up, hear the presentations.. If not, there are many youtube videos with some of the better teams presenting their on site. Here is one from Myron Mixon that I watched, of course everyone's is different... My team likes to keep it a little lighter, friendlier than he seems, but it gives you a feel of one way to go about it.
http://www.youtube.com/watch?v=zhdT2W-_1vo
Like LakeDogs, our team uses 2 - 3 people, depending on who is there. My team considers the presentation broken down into 3 parts:
1) Introduction (at gate) - who are you, how did you form, what do you stand for..etc..
2) Process (at smoker) - What do you cook on, what temp, what fuel, theories, practices.. etc.
3) Tasting (at table) - As LakeDogs described better than I can, flavors, smells, rubs, sauces.. etc.
We like to have an intro guy who meets the judge at the gate says hi, introduces the team and tells a little back story on all of us, then hands off to myself for explanation on the cooking process (wood, about cooker, temp, meat source, etc) , then I hand off like Lake Dogs does to my flavor guy who can really sell the complex profiles better than I. This allows a nice transition to the table without the judge waiting on anything or having downtime (silence is a no-no, always have something to say) in conversation with our set up.
Last thing, be prepared for not just 1 judge, but 3 for preliminaries, rolling into your site one by one in usually 20-30 min intervals i think.. LOTS OF MEAT!! You have to present them with their own fresh piece of meat on the smoker each time. Meaning you will have to cook at LEAST 5 shoulders if you make finals. Lets say you're only doing shoulders, your schedule will go something like this...
10:00am, turn in blind box = 1 shoulder
10:30am, on site for judge #1 = 2nd shoulder
11:00am, on site for judge #2 = 3rd shoulder
11:30am, on site for judge #3 = 4th shoulder
If you are doing ribs, that whole cycle restarts at noon with ribs blind turn in. Then, if you are called for finals in anything you enter, you have to have another new piece of meat ready for 3 more on site judges to come at once and do your whole presentation over again for all 3 simultaneously so make sure you have seating for 4.. This usually happens about 2:00pm (i'm guessing, as i've never made finals, hahaha)..
And that would be your 5th shoulder... Lots of teams cook more so they can have the pick of their best products... If you do ribs, definitely get a case, as you often have less than ideal cuts that will be delicious, but not the perfect visually appealing things you want to show to judges.