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With the first side of the attic ladder frame securely fastened, shift your attention to the opposite side. Take several peckers (thin wooden wedges) and snap them to a size that roughly matches the gap between the ladder frame and the noggin. Carefully insert these peckers along the entire length of the unsecured side of the frame. The goal is to create an extremely tight fit; if the fit is too loose, driving the screws will cause the frame to pull out of square, leading to an uneven and potentially unsafe installation. Once the side is tightly packed and the frame is held firmly against the noggin, use your drill to pre-drill pilot holes and then drive three 75mm wood screws through the attic ladder frame into the noggin, mimicking the pattern used on the first side (one at each end, one in the middle).