Climb up a ladder until you can easily access the roof. Walk to the location of the ripped shingle and count up two rows of shingles directly above it.
Lift up the shingle that is two rows above the ripped one and locate the nail that holds it to the roof. Slide the flat pry bar under the nail with force to snap off the nail and loosen the shingle from the roof.
Move down to the row of shingles above the ripped one, where two singles reside. Lift them up and use the pry bar to remove the nails there as well. Some of the nails will break off, while you may need to pry up others.
Move to the two shingles on either side of the ripped one and perform the same process to remove the nails from them as well.
Grasp the bottom of the ripped shingle and pull it straight down to remove it from the roof. The shingle is actually one of three that are all attached to a single strip.
Place a new shingle sheet into position where you removed the ripped one. Lift up the shingles above the area to slide the top of the replacement sheet under them. Stop when the bottom of the new sheet aligns with the remaining shingle beside it.
Insert a roofing nail at the upper left side of the new shingle 1 inch from the side. Insert another nail on the right side of the shingle 1 inch from the side. Then insert two more nails between the first two at equal distances.
Lift up the shingles in the two rows above the repair site and locate the holes from where you removed nails. Insert a nail into each hole and hammer it in flush with the roof to reattach the shingles. Insert additional nails into the two shingles on either side of the repair site using the holes of the nails you previously removed.