Mark a pencil dot six inches from one corner along one edge of a 36-inch square on the flat 36-by-36 side. Use the T square to measure perpendicularly.
Mark a second dot perpendicular to the edge six inches from the first dot.
Mark a third dot parallel to the edge with the first dot, six inches away from the second dot and six inches down from the first dot.
Mark a fourth dot perpendicular to the first edge through the third dot and six inches farther from the edge than the third dot. This new dot should be six inches from the opposite edge as the edge of the first dot.
Mark a fifth dot six inches down from the fourth dot and 12 inches down from the second dot parallel to the edge of the first dot.
Draw a six-inch perpendicular line from the fifth dot to the edge opposite the first dot.
Draw a six-inch line between the fifth and fourth dots, one between the fourth and the third dots, one between the third and the second dots and one between the second and the first dots.
Repeat on other square boards if applicable.
Cut exactly along the pencil lines of all boards with the saw. When one board is cut completely it should create two stair silhouettes of exact dimensions.
Place two 1-by-8 planks on the ground so the eight-inch face is parallel to the ground 20 inches apart lengthwise.
Stand one stair silhouette spanning the two boards roughly one inch from the edges of both boards. Mark silhouette width and location on the board and repeat with the other edge.
Measure distance between innermost marks on the ends. If using two boards, divide measurement by three and mark a silhouette board width at that measurement from both ends for a total of two more widths marked. If using a third board, divide by five and mark a total of four more widths at that measurement.
Drill four guide holes roughly one every inch and a half through the eight-inch plank at every spot where a width of silhouette was marked. Screws will be run up through the bottom of the planks and into the bottom of all stair silhouettes so attempt to keep guide holes centered in the marked width of the silhouette.
Align one plank with the extreme back of the bottom of the stair silhouettes and one plank with the extreme front, flip entire structure over and screw wood screws through every guide hole in and into the bottom of each silhouette. When returned upright, finished product should have two 1-by-8 planks running at the front and back of the stair silhouettes awaiting actual stairs to be laid over them.
Lay each 2-by-10 plank on one step of the stair silhouettes lengthwise to create a staircase with loose stairs.
Center stairs over the stair supports and mark locations of silhouette support widths on each stair.
Drill three guide holes roughly every two and a half inches through the center of marked silhouette support widths in each stair.
Screw wood screws through each guide hole on every stair.
Move wood stairs in front of the door.