What do we know about Bernard?
Draw a picture of Bernard and collect ideas such as physical appearance, age, gender, where he lives, hobbies and write around the outside, and ideas such as likes/dislikes, friends/enemies, feelings, secrets and dreams inside the body outline.
Some of these ideas you might be able to guess from looking at the book, others you might be able to make up. Remember you can be as creative as you like.
And if you don't have the book, you can remind yourself of the story by going through the text map or watching it on this youtube clip: