Autistic toddler help

So I suspect that my toddler is autistic. I ran through an M-CHAT-R, and he is high risk. I'm in the UK so will likely have to wait a very long time for any help from the authorities. In the meantime I would like to do whatever I can to help him.

I wonder if anyone has got any recommendations for books or resources that could help me learn how to help him learn/process/grow/deal with the world easier. He is 2 and 3 months and doesn't talk yet and I would love to be able help his speech development. I do read to him, sing to him, narrate my day etc. I have looked into techniques to help neurotypical children with their speech, but I wonder if there are different techniques for neurodivergent children. If anyone has any recommendations, please pass them on.