Car at the dealer acting

Moin, I would like to buy a Seat Leon Fr 1.5 liter Tsi. My question now how to act correctly ? The car should cost 26.985 Euro and has a mileage of 7 km, the first registration of the car was 09.2020. I would like to trade it down myself, but unfortunately don’t know how to handle it. I would be Bar Payer myself and would not have to finance it. The car house where I buy is a Seat dealer and not very small. I also got cars that are 400 km away from me. chaut, the zb cost directly 3000 euros less. Do you think that would be a good trade argument? Looking forward to your experiences, you can give me tips on how best to do it 🙂 Would I be very happy to answer, Best regards Christoph