Auction is coming up on 10-14 Nov in Cookeville TN. My first time selling, have 3 lambs ready for market, so I have no clue

Anyhow, one of the requirements for selling lambs is health certificates from a vet. Does anyone know how this process will work? i.e. is there a certain timeframe before the auction that this needs to be done.. Also, when having a vet do this check is it something that can be completed with one visit? Ideally, I'd like to schedule a visit with the vet and then head on over to the auction. Is that realistic?