Book recommendations please

I’m worried about starting school! My little one has a speech delay and has no clue what I’m talking about when I mention school. He’s not massively into reading as he just doesn’t sit still but I figured a book may be the best place to start - any book suggestions for starting school. Also any other suggestions to try? Now we know what school he has been accepted to I’m planning to wander past each week and explain that he will be going there etc. I’m planning to go to all the events in the run up to school that get offered. I’m just worried about him not being ready I suppose and want to make sure I’ve done everything I can to help the transition.