The New Day Tornado Shelter requires a quality slab under it, whether outside or covered.  Typically, the best place is inside the garage.  If your garage is attached to your house, perfect!  To decide exactly where, first imagine your garage devoid of everything.  Then imagine a circle just 3 1/2' across at a spot where you would have quick, day or night access from the house to the shelter, without climbing over stuff or moving the car.  We are not at all concerned if it is near a window or on an outside wall.  The main thing is that you are inside the shelter when you need to be!  Do you see that place where you could imagine this shelter standing?