What books or courses preferably free on Kotlin and Android development do you know?

Question

Android

Actually the whole topic is in the title.
I want to learn how to work on android, I rolled into Kotlin a little, looked at the syntax and examples, but without tasks to declare variables and classes, somehow about nothing.
Kindly advise suitable training materials: on kotlin and android development. Courses, books, YouTube channels. Maybe someone knows normal free courses.
Thanks in advance

Answer 1

https://developer.android.com/training/basics/firstapp

Answer 2

https://ru.stackoverflow.com/questions/732964/%d0%...