The clip they show is of the main ring which is where they do the agility, obedience, and the group judging (the top dog from each breed) and of course best in show - the clip you saw. The tickets for the main ring are sold separately and in advance, I go in there if I can but not always. The rest of Crufts is MASSIVE, there are the breed rings where breeds recognised by the Kennel Club are judged, starting with the puppies (6-12 months old) and up to the open classes (the dogs that have qualified through all the classes)... They end up with top dog and top bitch, the judge then chooses one of them as the best of breed, that dog goes into the group judging (toy, utility, hound, gundog, terrier, working and pastoral) and the winner of that goes through to try and win best in show.
The dogs are benched generally close to their breed rings and you can wander freely around them, although you are asked not to touch when the owners are not there to ask permission, which is obviously sensible.
There is also a Discover Dogs area where EVERY breed is represented EVERY day, these areas are manned by breed enthusiasts, so you can normally meet and greet dogs of very breed there, and the dogs (and handlers ) are chosen for their people skills. They will introduce you to their dogs and give you lots of information about the breed and whether it is suitable for you. You'll see all the breeds you are familiar with and others that you may never have heard of! I took Obi to the London Discover Dogs when he was a puppy to represent the Australian Cattle Dogs, it was great fun!
Strangely the Australian Shepherd Dogs are American! They're only called Australian as they used to herd Australian sheep - just a little factoid for you! :)
Sorry, I've gone on a bit... Can you tell I'm on my favourite subject?