When I try your second paragraph steps, I can get as far as creating a Journey (as a test, I created a Start, Waypoint, and Endpoint). it creates the journey fine - but the "Send Journey" button is not active, so I can't click on it.
As another test, I tried "Destination Send-To-Vehicle", and that seems to let me send something - but it's confusing. it asks me for a "Folder" and a "Feed". I can type a folder, but I have no idea what Feed means.
Bigger question - since I just bought this car, doesn't the dealer have experts in this stuff who can show me how it all works? I have to say as nice as the car itself is, the dealer service I have received has been horrible, almost as if the sales rep got the sale - now good luck figuring everything out.