To install attic rafter vents and baffles, first calculate how many rafter vents you need, and make a cardboard template of the soffit vents to cut them equally. After drilling holes and cutting according to the template, slide the soffit vents into the openings, and enter the attic to install baffles on the interior by stapling their tabs to the rafters and wall plate.
Install rafter vents prior to installing to baffles, since they attach to the interior of the vent receptacle. It may be necessary to position a sheet of plywood across the attic's interior rafters in order to maneuver inside in the attic. Additionally, wear a helmet with a headlamp to maintain safe and well-lit working conditions.
Before installing rafter vents, calculate the number of vents needed by measuring the area of the building in feet and dividing this figure by 150 to arrive at the square footage of the vent space. Divide this number by two to arrive at the number of vents required. Then, use a stud finder to find the rafters in the building's soffits. Place these vents along the back side of the building to make them less noticeable, and trace each vent using the cardboard template before sawing into the structure.