Thoroughly wash and dry your concrete surface using the soapy water and push broom (for larger areas) or scrub brush (for small areas).
Apply sealant to the cement according to manufacturer's directions. Allow to cure thoroughly.
Mix the floor paint very well using the paint stir stick. Pour some into a tray, if desired.
Lay the stencil down on the area you wish to paint and secure it to the cement with painter's tape.
Dip your foam or bristle brush in the paint, then go over the stencil with short strokes, pressing the stencil down with your fingers so that the paint doesn't seep underneath the stencil lines.
Remove the stencil and resecure it in another position, and repeat your painting motions. Move the stencil and paint as many times as is necessary to complete your project.
Allow the paint to dry completely, then seal the cement with another layer of sealant over top of the floor paint.