When to sign and what to sign? New 2019 trailer purchase.

I special ordered my travel trailer at a dealership and also had a lot of upgrades added. I got a larger ac unit and fridge, a hot rod installed for electric hot water and special upholstery. I put 1,000 down and didn't sign any loan papers. When the travel trailer arrived at the dealership, I did the walkthrough. Then, I went to the bank and signed the loan papers authorizing them to pay the dealership and took delivery on the trailer.