First Ryan put the Fascia boards on the ends of the rafters. Then he started putting on the rolls of roofing underlayment. Some people use felt or tar paper. I bought Liner Lock – 140 M a heavy duty premium grade roof underlayment with 100 % recyclable polypropylene water barrier. It is advertised to be 20 times stronger than #30 felt, and lighter weight. We will see if Ryan finds it easy to work with. He is securing it with roofing nails.
He will need to cut the 4 foot wide roll to fit on the lower roof.