Sketch the Design
Measure the distance between the door and the ground and sketch out a plan for the steps. Make sure the planned stairs are all the same height and depth, and that the stair height and width conform to local building codes. Use these measurements to determine the length of the stringers (supports) and the distance from the house to the base of the stringers. If a ledger board isn't present, install one and measure from the front of the board.
For greatest comfort, design the stairs with a 6" to 7" rise (height) and a 10" to 16" run (depth).