Lay paving stones down in a pattern so that no large spaces exist between each stone. As you reach the hose or piping perimeter lines on the pathways, mark on the stones with chalk where you will need to cut the paving stones so that they do not overlap the perimeter of the pathway.
Remove the stones that you have chalked and that are overlapping the pathway perimeter.
Saw the stones on the stone chalk markings so that they will fit and not overlap the edges of the pathway.