Position the ladder against the loft in the desired location. Mark two spots on each vertical board of the ladder where it comes in contact with the loft. Make these spots locations through which the bolts can be placed securely.
Drill a hole in each position using a 1/4-inch drill bit that passes through the ladder and into the loft itself. Replace the 1/4-inch drill bit with a 1/2-inch drill bit. Redrill the first 1/4-inch of the holes on both the ladder and the rear of the loft.
Pass a 5-inch bolt through a washer, the ladder and the loft board. Slide another washer over the exposed end of the bolt and cap it with a nut. Tighten the nut and bolt using the socket wrench. Repeat as necessary for the other bolts.