Go into your attic to find room for a set of stairs to enter. If you have no attic door, cut into the drywall or plaster ceiling and look into the attic. Ask a carpenter to guide you in planning where to place the opening. You will need to outline the opening from the attic side by nailing long nails beside joists to define where to mark the perimeter of the stairs. This is not a job for a do-it-yourselfer unless you've worked with a project similar to this.
Use a carpenter's square to draw the staircase opening on the ceiling of the room below the attic. Use a hand saw to cut through one rafter. Stand on an A-frame ladder or move into the attic area to make additional cuts. Never saw through a double beam, since this is a support beam holding the structure of the house intact. Build a frame of lumber boards to fit the perimeter of the opening allowed for the stairs. Use nails and screws to secure the framing box tightly. This box becomes the support system for the rafters you've just opened, so use stainless steel flathead nails and screws that are at least 4 inches long.
Measure the length for the stair stringers. Have a carpenter help you gauge this precisely, since the stair stringers must be placed in the attic opening to the floor below. Stringers support treads nailed across them to make the stepping part of the staircase. Cutting it too short will waste the entire piece of lumber. Create each of the two stringers out of 2x12 boards, or have them cut for you at a local carpentry shop. Use screws or a nail gun to secure the stringers to flooring and at the top of the attic opening.
Cut treads for each step out of plywood or buy premade treads to nail onto the stringers. Decide if you want to enclose the front of each step with a riser. If so, cut enough to fit on the front of all steps. Use small nails without heads and glue to install the treads and risers. Use a carpenter's tool to counter sink the nails below the surface of the wood slightly. If the attic steps will be visible from a finished living area, you might invest in risers and treads that are made of upscale materials and ready for painting or staining.
Enclose the sides of the stairs using drywall or wood paneling. Buy upscale paneling versus plywood paneling if your budget will allow. Leave room under the stairs for storage, if you desire. Build or buy a small door to install on the side of the staircase. Attach fittings on the wall for a wooden hand rail. Use a stud finder to figure out where to attach the metal fittings to wall framing to hold the handrail. Buy a length of premade handrail and screw it to the fittings from the underside of the handrail.