Concrete decks come in all shapes and sizes, but there is one thing that is nearly universal about them: if they are left unstained or unpainted, the gray concrete is utilitarian and boring looking. In the case of a deck that has already been built, it is too late to stain the concrete, so painting is the best means to quickly and easily beautify the deck.
Sweep the deck of any debris, and then hose it down to wash it. Let it dry completely. Then sweep it once more to get rid of any debris that collected in the meantime.
Pour a small amount of the masonry sealant and primer onto the deck, then use the paint roller to cover a small area with it. Continue to work section by section, keeping the exit at your back so you don't paint yourself in.
Leave the sealant to dry as directed by the instructions. Drying time is typically several hours.
Pour a small amount of paint onto the deck, then use the roller with a fresh sponge to cover an area with it. Continue to work section by section, again keeping the exit at your back. Be liberal with the paint, covering the deck with a thick coat, to avoid the need for a second coat.
Let the paint dry completely.
Pour a small amount of the clear sealant onto the deck, then apply it with a fresh sponge on the roller the same way you applied the primer and paint.
Let the sealant dry according to the package directions.