Each breed is shown differently. I will give you an example of Dutch, Jersey Woolies, Netherland Dwarfs, and Belgian Hares.
Dutch:These are shown in Varieties (Colors).
First, the rabbit must place 1st in its class. Say the class is Black Senior Bucks. The rabbit will then compete against all the 1st place Black Variety rabbits (there are 4 in Dutch: Sr. Buck, Sr.Doe, Jr. Buck, and Jr. Doe) The judge will chose Best of Variety and a Best Opposite of Variety (must be opposite sex than the BOV). These two rabbits will go on to compete for Best of Breed and Best Opposite of Breed. Since there are 6 showable colors in the U.S. for Dutch, eventually you will have up to 12 different animals on the table for Best of Breed and Best Opposite of Breed, two from each variety. Only the Best of Varieties can be considered for Best of Breed. Once Best of Breed is chosen, the judge will excuse all the rabbits of the same sex because Best Opposite Breed has to be a rabbit of the opposite sex. So if the BOB is a Buck then all the bucks are excused and the remaining 6 does will compete for Best Opposite of Breed.
Jersey Woolies: These are shown in Groups rather than in Varieties because there are 24 different colors recognized. Everything else is the same like the Dutch but insert the word Group in place of Variety.
Belgian Hares are the same except they have one recognized variety in the U.S. Therefore, all 1st place animals are considered for Best of Breed. Opposites of the Best of Breed are considered for Best Opposite of Breed.
Netherland Dwarfs are more complicated. They are shown in colors and the colors compete for Best of Group. So they have an added step. They can will Best Black (for example) and Best Opposite Black and these compete against the Blues and the Chocolates (there are more in that group) for Best of Group. There are 5 different groups in the Dwarfs.
Breakdown:
1st place - BOV & BOSV (or BOG & BOSG) and then BOB and BOS.
Hope this helps and sorry if this is confusing. If you give me a breed you are interested in showing or learning more about how they are picked, let me know.
Sharon
Edited to add: At the end of the show, all Best of Breeds are eligible to compete for Best of Show. Some shows pick a Best Reserve too, others Pick Best 4 class and Best 6 class with these two rabbits alone competing for Best In Show.
4 Class is for rabbits that only have Sr. Buck, Sr. Doe, Jr. Buck, and Jr. Doe (4 classes)
6 Class is for larger (more than 9 pounds) that have a 6-8 month class for bucks and does too. Therefore they have 6 classes.