If I was to place the tiles on a front concrete porch with just a small stoop over it, would I need to glue them down? Would they blow away if there was or wasn't any trim around the edge or glued down?

Using an adhesive is optional. You may simply install these tiles without the glue, and the weight of the tiles will help them stay in place. However, if you see them move too much, using a pressure-sensitive adhesive will help them stay in place.