Put in the Underlayment: Get started on the eaves (the sting of the roof) and roll out the underlayment, overlapping each row by about 6 inches. Nail the underlayment set up with roofing nails. This is often my 2nd time using HCR to put in the remainder of my windows. https://devinpdpbl.gynoblog.com/34555613/the-5-second-trick-for-residential-roof-installation