Instantiate position tracking?

I have never used this, but looking at the docs you need to use this

After instantiating a new object you want to set your transform to it's x-max:

transform.position = Vector3(newObject.collider.bounds.extents.x,0,0);

The thing is though, your new instantiated object (which is random you said) will now be instantiated partly inside your previous object, because you compensated for the previous object's x-width, but not the new one's. So say first you used to instantiate at the position of the object you keep on moving to the right, now you want to instantiate at

newObject = Instantiate(object,Vector3(transform.position.x+object.collider.bounds.extents.x,transform.position.y ,transform.position.z) 

If these objects have no collider, replace it with renderer.