When the first letter is put at the end, and 'ay' is added after that.
If it begins with a vowel it is the same, but 'way' is added instead of 'ay'. But 'a' is different, because it is the only one letter word, which is a vowel, so you change it to way.
hello = ellohay
goodbye = oodbyegay
a = way
and = andway