I basically paired mine through the menu. Now when i get in the car it automatically connects. I have noticed that when I connect it with the cable to use carplay, when I unplug it it doesn't connect on it's own then. I have to connect it manually.
Is it currently paired with something else that's also in the car? I know there's an issue that it can only connect to one phone. So if you've paired it with two phones (for example, you and your spouse) and both happen to be in the car at the same time ... it will pick one and ignore the other. In that case, you have to select which phone has "priority" if both are present. The details should be covered in the owner's manual.