You do not say which country only the shows. If you are in UK generally you need to get in touch with show and an application form and fill it in pay your money and follow the rules. It is easy but rules are bit funny. All items have to be at least I metre in at least one direction. They also need to know sizes of quilts well in advance of the show I bet some hint ven started . Money for insurance an postages appeared complicated but really was not. They also pick age and send back for a price and of course insurance. You also , if you go to the show, need o be very thick skinned especially if you walk past as people ar discussing the quilt. . I found it difficult to divide which category mine went in and one was wrong. Paperiecing not traditional. . .
I enjoyed it but not sure i would do it again I'm not competitive enough.