Start at the eaves and work up to the top. Apply felt adhesive, or liquid felt, liberally all over the roof. Apply the first row of felt over the eaves. Leave a few inches over the edges to form tucks so the rain drips away from the walls of the shed. Leave a couple of inches on overlaps so the water runs onto and not under the previous row of felt. Use large head felt (roofing) nails every 6 or so inches along all the edges, and try to use liquid felt or felt adhesive under and on top of all joints. Apply liquid felt with an old paint brush. All mineral crumbs can be collected to cover the nail heads and camouflage them. The top ridge felt covering should be stuck with felt adhesive and then nailed to make it stronger and last longer.