Porch steps are necessary if your deck is above the ground level. By following these instructions you can make sure to avoid mistakes. Use pressure treated 2 inch by 12 inch lumber, carefully picking out the straightest and most knot-free lengths. First measure how far out from the deck of the porch the steps will go; the further out, the less the incline or steepness. Check local building codes for the incline. Determine the stair width you want; the stairs will be 12 inches deep.
Supports for the stairs are called stringers. They can be pre-fabricated or cut on site. If you are going to make your own cuts, you will need to learn how to use a framing square. Use one stringer for every 18 inches of stair width, so if the stairs are 36 inches wide, use three (one for each side and one down the middle).
Measure the total height (the rise) from the deck to the ground. If the ground is uneven, measure to the lowest level. The International Building Code specifies a height of 6 ½ inches for rise. Divide the total rise by 6.5 and round the number down. (Check with your local code.) Attach the stringers to the deck using angle brackets and lag bolts. Screw the treads and risers to the stringer with 3 inch deck screws.