Use these letters to talk about baptism. For younger children, talk about each letter and let them tape it on the wall. For older children, give them the letter and have them tell all they know about what is written on it, and what it has to do with baptism, for example, "P" - partaking of the sacrament - is what we do to renew our baptismal covenants.
You may want to put them up in a different order, depending on the topic you want to talk about first. You may want to use the "B" first or last though, so you can introduce or conclude with "Baptism"
Talk about the experience when you were baptized. Or tell about when your ancestors first joined the church and their experiences getting baptized.
Bare your testimony about the importance of baptism.