This is particularly useful for immersing pupils in a story and to help them consider all their senses when reading, rather than just focussing on what they see. Choose a scene from your book, then ask groups of pupils to think about what they might hear in the background of that scene.
So, if you were reading a story based in a jungle or forest, the students could use their voices to replicate the sounds of birds, of leaves rustling and so on. Have the pupils perform their soundscapes to the class, and if possible record them.
Once complete, you could read out the linked scene from your story with the recorded soundscape in the background. Doing this with a recording means that you can make sure the volume is audible but not overwhelming, and also allows everyone to focus on being immersed in the story rather than making the sounds.