Imagine you have a big piece of paper and a bunch of magazines with pictures and words on them. A collage novel is like making a big story puzzle with those pictures and words.
You can cut out pictures that show characters and scenes from a story, and glue them onto the paper in the order they happen. Then, you can add words that tell what the characters are thinking and saying.
The collage novel can tell one big story or lots of little stories that connect in a special way. Just like a regular book, you can read it from beginning to end and see how everything fits together.
So, to sum it up, a collage novel is a cool and creative way of putting together a book using pictures and words from different sources.