Determine the desired size of the deck by using the tape measure to measure the approximate height and width, then jot these numbers down on the scrap paper. If possible, look at other deck designs for various design ideas, such as any lattice work around the deck, placement of the steps and any desired railing. Jot this information down as well.
Draw a rough sketch of the back of the house on the paper to show the back door's position in relation to the deck. Leave enough room on the paper to create two separate drawings: an overhead view of the deck to show overall deck space and a side view to show height.
Sketch the deck's perimeter on the paper, then write in the dimensions that were jotted down earlier to show the length and width of the deck's surface. Multiply these numbers together to determine the overall top surface space on the deck.
Sketch the side view of the deck, again sketching the house and adding the ground to give the contractor some idea of how high the deck will sit above the ground. Add in any lines to the open sides under the deck to show lattice work (if desired) and draw in the height of any railing work.
Transfer the sketches onto the graph paper, using the ruler to create straighter lines if desired. Write down the same measurement info from the scrap paper on the appropriate spaces on the graph paper drawing.