At this point you now have a wooden box filled with wet concrete that looks nothing like a walkway. Relax. Getting the finish product that you desire is just a few steps away.
First, use the extra 2x4 to begin leveling the concrete with the top of the form. This process is called screeding. Rest the 2x4 on the top rails of the form, and with one person on each side, quickly move the 2x4 back and forth in short strokes, pushing the wet concrete from one end to the other. This will accomplish several things. It will level the surface by pushing any extra product that you have over the edge of the form. Second, it will begin to push up the excess water that is in your mix. This is vital if the concrete is to cure correctly. Make your way across the entire surface of your walkway, wait a few minutes, and then do it again. The excess concrete that spills over the edge can be used to fill in any low spots that you may find.
After screeding the surface twice, or maybe even three times if you still have low spots, it's time to get your float and begin smoothing the surface. The float is designed to do just what its name implies. You do not want to apply a great deal of pressure, as this will create an uneven surface. Instead, you will find that as you pass the float over the surface, it will actually pull water to the top and the water will create a nice smooth finish. It will take a little touch, but after a few minutes of practice you will be floating like an old pro.
Once the concrete begins to stiffen to the point where you can put your finger in it, and the hole doesn't close back in on itself, then it's time to do three things. First, fix the hole that you just made with your finger by going over the surface with the float one more time. You will find that, the more the concrete stiffens, the nicer the surface will remain after you float it.
Second, it's time to mess up your fresh newly floated surface if you don't want to fall on your face the first time it rains. Smooth, wet concrete can be extremely slippery. Take the stiff broom and drag in slowly across the stiff, but still wet surface. Don't push, just let the weight of the broom do the work. It will create a nice textured surface that will be slip resistant. The carrier of your homeowner's insurance policy will love you for doing this.
Third, take your edging trowel and begin to go along the edges, creating a nice looking finished product. You can also measure off 36" to 42" sections and use the trowel to form breaks in the walkway. Not only does this look nice, but it creates a natural water run off and helps prevent ice problems in the winter.
After a few hours, use the pointing trowel to separate the pour from the forms. It's much like using a spatula to separate the edges of a cake from the pan. Gently insert the sharp end of the trowel's nose between the concrete and the form, taking care not to mess up your edge. Once it's been separated, you can begin removing the screws and taking up the boards that make up the form. It is possible, and sometimes recommended just so people don't walk on your still wet walkway, to leave the forms in place for a day. You still need to use the pointing trowel to make sure it's not sticking to the form while it's wet, but you can then leave the form in place as it serves to announce to folks that the sidewalk may not be done yet.
Brian Simkins is a freelance writer living in Chicago. He enjoys using his 14 years of home improvement experience to educate and equip new home owners.