Clean the concrete surface you want to color by spraying it off with water from the garden hose. Wash the surface thoroughly, using the push broom to scrub away hardened dirt and other debris if necessary.
Allow the cement to dry before coloring it. On a warm, sunny day, this may take only an hour or two, but if the skies are overcast and the temperature is chilled, it could take up to four hours.
Pour the concrete sealer in the color of your choice into the paint pan.
Apply the sealer to the concrete surface using the paint roller. Do this in the same way you would apply paint to a wall by rolling the roller in the paint pan to coat it with sealer, then rolling it onto the concrete. If there are any corners, start at those points and work outwards so that you don't have to walk across the concrete until the color has dried.