Hi Kumar,
What do you mean by aligning objects? Your car looks fine to me, so I currently do not know what your goal is/was.
Since Unity is not a 3D modelling software, its options are very limited. If you cannot align the objects perfectly, don’t worry. If you really want to model your own assets for your game, it’s advisable to use an actual 3D modelling such as Blender, and import your meshes into Unity. This course mainly focuses on programming, though, so we do not spend that much time designing but use premade assets instead.
See also:
- Unity Manual: Positioning GameObjects
- Unity Manual: Grid snapping
- Forum User Guides : How to mark a topic as solved