The following online resources and books may be helpful to read about ADHD and ASD:
www.childmind.org - good resource for ADHD, ASD, behavioural difficulties
https://childmind.org/topics/adhd-attention-problems/
https://childmind.org/guide/parents-guide-to-adhd/
https://childmind.org/topics/autism/
https://www.russellbarkley.org/
Books for parents:
Russell Barkley - Taking Charge of ADHD, Revised Edition: The Complete, Authoritative Guide for Parents
Russell Barkley - 12 Principles for Raising a Child with ADHD
Books appropriate for children with ADHD:
My Doctor says I have ADHD, a child’s Journey (for ages 6-12) by Dr Yemula
All Dogs have ADHD – nice book to help younger children with ADHD learn about ADHD and their own features