I advise showing up early. Usually they'll have lists posted on the judging table-the judge's name, the breeds they are judging and the order they're going in. If you can find the table(s) where the Flemish will be and set up nearby. There is no set time for them to go up, so if you know they're coming up soon, stay close! If you miss the judging they will not judge your rabbit.
There is usually a lot of downtime, so like Feathers said, walk around, say hi, ask questions. Many times there is at least one vendor there-it might be a good time to pick up something you need without having to worry about the cost of shipping.
Good luck! Let us know how it goes!