Check with your local zoning board to be sure that your desired steps are in accord with the regulations of the local building codes. Some area require specific additions such as hand rails for steps over a certain height.
Level the ground where you want to place your stairs. Remove the sod from the area and dig out the spot 6 inches deep.
Use a tamping stick to pound the area to a hard surface that will prevent soft dirt from caving in under the weight of the concrete. Backfill the area with gravel. That promotes drainage and keeps concrete from buckling in freezing weather or cracking from water seepage.
Build your frame using 2-by-8 boards for straight edges and 5-ply plywood for any curved surfaces you desire. Cut 2-by-4 boards into short spikes and pound them into the ground surrounding the base of the platform to brace the platform. Keep each step the same height, and make each step at least 10 inches deep from front to back. The final landing step should not be less than 3 feet deep.
Set the carpenter's level across the form at all angles to check for uniform height. Make the necessary adjustments to ensure the entire assembly is level.
Nail braces to the stakes and push them against the 2-by-8 framework and nail it for a solid foundation. Concrete is heavy and must have a very solid surface to push against when you pour it.
Place a 1/2-inch joint expansion inside any area where concrete will abut foundations or house walls.
Coat the inside of any wood that will be in contact with the concrete with form oil. This allows you to remove the braces and forms easier, but doesn't stain or moisten the actual concrete.