Draw with a ruler on graph paper two rectangles measuring 6 inches by 1/4 inch, parallel to each other. Align the long side of both rectangles with the paper's vertical edge. Ensure the tops and bottoms of the rectangles are aligned horizontally, and that the space between the rectangles is 4 inches. This step depicts the top view of the front and back beams of the lean-to shed's floor. The size of the final shed will be 6 feet long by 4 feet wide by 8 feet high.
Draw two 4 x 1/4 inch rectangles capping the top and bottom of the two rectangles you just drew. These represent the top view of the left and right sides of the shed's floor.
Draw, a few inches to the right of the floor drawing, a duplicate of the floor. This forms the basis of the shed's roof. Draw three 4 x 1/4 inch rectangles parallel to the floor's left and right sides, and spaced evenly between those sides.
Draw a rectangle 8 x 1/4 inch to represent the right side view of the lean-to shed's back beams. Draw another rectangle 7 x 1/4 inch, placed 4 inches to the right of this step's first rectangle. This represents the side view of the shed's front beams. Draw a 1/4-inch wide rectangle extending from the top of the back beam to the top of the front beam. Draw another 1/4-wide rectangle spanning the bottoms of the back and front beams. These last two rectangles represent the shed's floor and roof.
Draw two 6 x 1/4 inch rectangles spaced 8 inches apart, aligning the rectangles' long sides with the horizontal edge of your paper. Ensure the rectangles, which represent the front view of your shed's ceiling and floor, are parallel to each other.
Draw two 8 x 1/4 inch rectangles parallel to each other, spanning the distance between the floor and the ceiling on the left side of the shed. Repeat this instruction to span the floor-ceiling distance of the shed's right side. This step, which completes the front view of the beams that support the ceiling, completes the plans for the shed.