Prepare the area, clearing out all grass and weeds and other debris to make enough room for the forms.
Dig the footings section about 1 1/2 feet wide and to the same depth. This will be the perimeter of your slab and your excavation will slope up the inside edge to the slab proper.
Lay the forms for the footings with 1-by-12 inch boards, filling the bottom of both the footings and slab with gravel to a depth of 6 inches. Use narrower 2-by-4-inch boards for the slab. Stake the boards to secure them, about every 12 inches.
Place rebar in the footings and raise it off the gravel using rebar stools, securing it with metals ties. Spread wire mesh on the slab area to reduce its chances of cracking. Now both sections are reinforced.
Pour both areas together and at once, using a pumper as part of a monolithic pouring system.
Screed the poured concrete with a perfectly flat-edged board, usually a 2-by-4- inch piece. Smooth the surface with a bull float.