Clean the surface thoroughly using a broom and hose. Spray the surface while brushing any dirt and debris from the surface of the concrete. Allow the surface to dry before staining.
Mix the chemical stain into the pump sprayer. Some stains require diluting. Follow the manufacturer's instructions for proper proportions of water to stain.
Hold the pump sprayer handle in front of you at an angle pointing toward the ground. The nozzle should be approximately one foot from the surface of the concrete and set to a broad spray pattern, as opposed to a stream. Move the nozzle back and forth slowly to get an even coat. Work in small sections to avoid tracking dirt into the stain by walking on it.
Brush the chemical into the concrete using a broom. Allow the surface to dry in accordance with the manufacturer's directions. Reapply as necessary to obtain the color desired. The color will darken as you apply more stain.