Cut the 2-by-4 boards to the dimensions of the form you require for the concrete.
Dig the area of the ground you will cover with concrete down to the preferred depth.
Drive the stakes into the ground at regular intervals around the perimeter of the area in which you will pour the concrete.
Attach the 2-by-4 forms to the stakes using the C clamps.
Place the bottom of the level on the top of each form to determine each form's gradient. If you wish the concrete to be level, aim for a zero gradient on each form.
Nail the stakes to the forms and remove the C clamps once you are satisfied with the gradient on each side.
Spray a bit of water lightly over the entire area with the garden hose.
Fill the form with the concrete and compact the concrete into the form using a 2-by-4 or roller tamper.
Level the concrete using a 2-by-4 so it doesn't spill over the sides. Allow the concrete to set long enough to support the weight of a wood plank.
Cut expansion/contraction joints every 4 to 6 feet using the groover and a straight wood plank as a straight edge.
Give the concrete an attractive finish using the trowel or a broom. You can be creative with this, but standing water can eventually cause concrete failure, so try not to create patterns or designs that inhibit water from flowing off the concrete.