Install the last course of field shingles on both roof slopes up to the ridge
Snap a chalk line along the ridge if needed for alignment
Cut shingles into ridge-cap pieces if using 3-tab shingles
Use preformed ridge-cap shingles if available
Start at the end opposite the prevailing wind
Bend each ridge-cap piece evenly over the ridge
Nail each piece with two nails, one on each side, below the exposed edge
Overlap each piece according to the shingle manufacturer’s instructions
Keep nails covered by the next overlapping piece
Continue along the ridge until you reach the end
Trim the final piece to fit neatly
Seal exposed nail heads if required by the shingle manufacturer
Check that all ridge-cap pieces are straight and securely fastened