Ogham is a primitive writing system of slashes and dots that was used to inscribe names on gravesites and standing stones. However, some scholars commented saying that it's inefficient, monotonous, complicated, and too cumbersome for daily use. So when the Roman alphabet was introduced in the fifth century, the Irish used it as the primary way to record their ancient myths and legends. Ogham letters are lines chiseled into stone post. This is how Ogham alphabets are illustrated: An Ogham "B" is a single line chiseled into the stone post to the right of the stone post's edge. Here is a picture that will guide you how it's written.
http://www.irishcultureandcustoms.com/AEmblem/BooKells.html http://www.irish-society.org/home/hedgemaster-archives-2/places-artifacts/the-ogham-alphabet
http://www.irishcultureandcustoms.com/AEmblem/BooKells.html http://www.irish-society.org/home/hedgemaster-archives-2/places-artifacts/the-ogham-alphabet