Several people have asked how to use letting templates, I'm not sure myself, please help.
There are a couple of ways.
You can figure out what you want it to say, and then take a piece of foam, lay your printed message out and prick thru the paper with a pin into the foam. When you are done, the backside of the paper is textured. You then take the paper and gently rub it onto your crusted buttercream, it will leave the pattern of the letters in the buttercream. You then 'connect the dots' with your butterceam and a # 1 or #2 tip.
Another options is to print out your message in reverse or if you can see thru the paper just flip the paper over. Go over your message with royal icing and let it dry. Once dry, you can use that as an 'impression mat' on your crusted icing. Pipe over with buttercream.
you can also print it out, lay a piece of wax paper over it and pipe royal icing over the letters.. Once dry remove from paper and place on your cake.