For a beginner, fusible appliques are easier then needle turn. You can google simple car shapes and print them out. Once you have your drawing, you can transfer it onto the paper back of a fusible like Wonderunder or Misty fuse. You iron the fusible to the back of your fabric and then cut out the shape with your scissors. Peel off the paper back and iron it onto your background fabric. You will need to machine stitch the edge to keep it from coming off after washing.
If that sounds like more then you want to try, Google preprinted fabric panels and look for one you can buy with cars on it. You can make your quilt sandwich and quilt around the cars on the panel.