Inspect the roof deck for damage, rot, and loose nails
Replace any damaged sheathing
Install drip edge along the eaves
Install underlayment over the roof deck
Install ice and water shield where required
Snap chalk lines for alignment
Start with a starter strip along the eaves
Begin shingle rows at the lower edge of the roof
Offset each row according to the shingle pattern
Nail shingles in the manufacturer-specified nail zone
Use the correct number of nails per shingle
Keep nails straight and flush, not overdriven
Continue laying shingles up the roof in courses
Trim shingles at valleys, hips, and edges as needed
Install flashing around chimneys, vents, and walls
Cap ridges and hips with ridge cap shingles
Seal exposed nails and cut edges if required
Check for proper alignment and coverage as you go
Clean up debris and inspect the finished roof