It's pretty straightforward. You will get notifications on your app for next steps. For me, they reached out to me to see if I wanted to change the option to loan or keep it cash. Asked them to change it to loan, then you can play around with numbers in your app. (Such as monthly payment/down payment)
It's nothing like buying a car at a dealership for sure. Not much to worry about or have that weird feeling you are getting ripped off somehow.
The app will show you the detail costs on the build you made, and all the final fees.
My first YLR I applied for the loan few weeks before my delivery window, but the car was pushed back, and the loan had expired.
This time, I waited for the VIN to apply for the loan. But I think the loan is good for 60 days or so now, it was 30 days in the past (I could be wrong)