In dictation, a short written piece is read out loud to the child, who then writes it word for word on his paper. He should attempt to use proper spelling and punctuation.
I simply choose a sentence or more (depending on the child’s development), read it aloud slowly, and wait for the child to write it in their notebook. We then go over the written work together, with me gently making corrections. It’s a very short, yet easy, exercise to implement. It teaches the habit of paying attention, as well as sentence structure, punctuation, spelling, and so on.
You could use pieces of great literature or nonfiction books on favorite topics. All found at the library or simply pulled off your own bookshelf.