Roll a piece of gumpaste to about 1/16 of an inch thick using a non-stick board and rolling pan.
Rub a small amount of vegetable shortening on the alphabet mat to prevent the gumpaste from sticking. Place the gumpaste on the letter that you wanted to use and roll the non-stick pin until it perforates the side of the letter.
Clean the edges of the letter by rubbing the sides with your lightly greased finger tips.
Carefully lift the side of the letter using a needle tool
Turn the letter right side up. Moisten the back side with a little edible glue or water and stick on the side of the cake or on top of cupcakes.