Excavate the area for the pathway, removing all rocks, grass and weeds from the entire length and width of the path. If you want the stones to be at ground height, dig the path as deep as the average height of the stones.
Install landscape edging along both sides of the path if desired to define the barrier between the path and lawn. Edging is typically driven in with stakes through holes in each piece of edging.
Places the stones directly on the soil in the desired pathway, leaving some wide gaps for moss to grow. Place the stones with the flattest side facing up and add or remove soil as needed to accommodate raised parts of the stones.
Fill in the joints between each stone with clean soil, leaving at least 1/2 inch of space to the top of the stones.
Remove as much soil as possible from a clump of moss.
Mix the moss in a blender with 4 parts buttermilk; if you use 1 cup of moss, you'll need 4 cups of buttermilk. The total amount of moss and buttermilk needed varies depending on the size of the pathway and the amount of space left between each stone. Blend the mixture just well enough to thoroughly break down the moss.
Pour, spray or sprinkle the moss mixture evenly onto the soil around the stones; you only need to use enough to saturate the soil. If you wish to have moss-covered stones despite the slipperiness, brush the mixture directly onto the stones with a clean paintbrush.
Mist the soil regularly with a spray bottle of water to maintain the proper growing conditions for moss. If the pathway is already located in a damp area, this may not be required.