Is there a fixed amount of cars at start of your application or shall they be editable during runtime?
With Qt you can use a widget based gui or a qml one - your choice. As ambershark mentioned the documentation of Qt is a good point to start with.
Qt Creator is a really good tool to work with Qt.
For starters it might be easier to use the designer and compose a gui visually.
First of all you should think about how you want to display your information to the user of your application. Maybe a simple list or a table of available cars.
Second thought should be - do the data needs to be edited by the user?
I started working with Qt years ago with version 2.3 and at that time i had to use MSVC or KDevelop to create applications. QT Creator is really a big step forward and i prefer using it while coding Qt based applications.
And yes - Qt is lots of fun!