Summarize the following:
Once your pastry bag is ready, you can pipe the icing on as an accent for the cookies. You can use it simply to outline the shape of the cookie, or to add fine details, such as a face for a gingerbread man cookie. You can also use the icing to pipe patterns on the cookies, such as an all-over polka dot or stripe design. Royal icing works extremely well as a glue to hold decorative candies and other embellishments on the cookies. Just add a dot of the frosting onto the cookie where you want to place the decoration and press the candy into place. When the icing dries, it won’t move.  You can use candies specifically meant for cookies decorating, such as sugar pearls or dragees, or you can use regular candies, such as M&M’s. Allow the icing to dry completely before you place the decorated cookies in storage containers. If you want an easy way to decorate the cookies, use a knife to spread the icing over the entire cookie. While the icing is still wet, sprinkle colored sugar over it for a colorful, sparkling look. You can use a single colored sugar for the entire cookie, or use a piece of paper towel or a paper plate to block off sections of the cookie as you sprinkle to use multiple colors for a striped effect.

Summary:
Pipe some lines on cookies with icing. Use icing to serve as glue for candies. Spread icing across the entire surface.