To install roofing felt, set the roll on a bottom corner of the roof, unroll a small amount of felt, nail it to the roof, and repeat until you reach the opposite end of the roof. Use the same technique to cover the rest of the roof in horizontal strips of felt. The supplies you need include a ladder, roofing nails, a hammer and roofing felt.
Set the felt roll at one bottom corner of the roof, unbind it, and unroll several feet of felt. Adjust the felt so it lies flush with the bottom edge of the roof, and fasten it with roofing nails. Unroll the felt to the middle of the roof, keeping the bottom edge aligned with the roof edge. Hammer nails to the middle, bottom and top of the felt, and then roll additional felt until you reach the opposite side of the roof.
Pull several more feet of felt off of the roll, and then cut it with a knife. Set the roll aside, pull the felt to the edge of the roof, nail it down, and cut off any excess. Install the second felt course with the same technique, overlapping the first course by 2 inches. Lay additional overlapping rows until you cover the entire roof.
Inspect the felt. If you find wrinkles, slash them with the utility knife, and drive nails through the edges.