You haven't done nothing else besides that, right? Obviously the model needs lot of work to be properly made to work in MM2, it isn't already done and what you have to do is only export it in .pkg file.
Check and keep training with
this tutorial made by Silent1Unknown to know the basic things, from the objects using and naming to the folders preparing and .ar file creating. Jump the first steps about make the car model; in the archive is included an example car. The two templates present
here at the bottom of the page can be helpful.