I was a member of Bradford and District for many years. (Y.A.A.S. Yorkshire association of Aquarist Societies) On open show day You will probably pay a nominal fee on the door, then again you may not. Fish for the show will be benched according to the times on the program. You will be able to look around at your leisure unt judging starts, then usually what happens is that there will be an auction, (Good place to get bargins on both fish and equipment) When the judging has finished you can again view the fish. After the auction and de-benching of the show fish there is usually the prize giving for the winners, cullmanating in Best in Show trophy.
My advice is to go along, join your local society. They are great places of learning. Contact the secretary for further details
Enjoy your day out
Regards
BigC