Dry the surface. For installation take a pump type spray bottle, put a quart of water in it and add 2-4 drops of dish soap to it. Once it is mixed, lightly mist the surface of the transom with the dilute soap solution and install the lettering. The soap solution lets you move the letter around a bit and also squeegee air out from under them. Once you have the lettering on, don't coat it with anything for a season or you will trap the moisture from the misting under the letters and they will bubble. After one summer, you can wax or even varnish over the letters