Run string along the intended walkway line. Make the pathway 3 feet wide.
Plunge a spade into the ground along the string marker to create a guideline.
Dig the entire pathway down 3 to 4 inches. Cut through any large roots with loppers
Set long pieces of flexible steel edging along the edge of the pathway. Slide a spike into the metal clip on the back of the edging and pound the spike into the ground with a hammer.
Cut two notches with a jigsaw 3 feet apart on a two-by-four and place it over the steel edging to keep the steel in place.
Unroll a sheet of landscaping fabric into the walkway to keep roots and plants from growing up into the stone.
Spread a 4-inch layer of pea gravel into the walkways, spreading it even with a rake.
Place the slate onto the pea gravel, best side up. Wiggle the slate into the pea gravel, then hit it with a rubber mallet to work it into the stone. Repeat with each stone in the walkway.