How do I negotiate a car deal when I already have a preapproved car loan?

So I got preapproved for 12,000 at Navy Fed Credit Union (I only plan on spending at most 7500 of it though). Now, I know not to disclose that I'm preapproved with them to begin with, but how would I go about negotiating the price without saying that I will be paying with a loan? When exactly do I disclose to them that I have a loan to pay for the car? Basically, all in all what can I do to maximize my benefit when dealing the car I want? I also have about 2500 cash saved up that I can spend so am I also able to use that and then cover the rest with the loan? For example, I'm looking at a Honda Accord listed for 6995, can I use 2500 and pay the 4500 hundred and taxes and such with my loan?
Thank you in advance (:

Read more: How do I negotiate a car deal when I already have a preapproved car loan?