I have always recommended Mike's "in easy steps" books introducing programming languages but sadly he has not done a great job on App Inventor. You would be better off using the free Tutorials and Books by the App Inventor MIT team, plus the Tutorials and Guides on the forum and the tons of material posted by the Power Users on their own web sites.
Lots of good tips, tricks, code snippets and links (including MIT tutorials) on my site:
Invaluable detailed guides on TimAI2's website, especially saving and retrieving data from the cloud:
Exchanging data with external devices (microprocessors such as Ardunio, ESP32)
on Juan Antonio's site:
http://kio4.com
Frequently asked Questions:
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