Answer 1

Pls visit kotlin official site to learn more.
https://kotlinlang.org
otherwise you can directly download this pdf
https://kotlinlang.org/docs/kotlin-docs.pdf

Answer 2

Good news!
Kotlin is now live in SoloLearn!

https://www.sololearn.com/Discuss/1319472/?ref=app
https://www.sololearn.com/learn/7792/?ref=app

Answer 3

How did you find SoloLearn? Rinse & repeat the same method for anything you're trying to find. Unless you asked some random discuss on how to find SoloLearn, in which case, you're beyond the help I can give. :)

Answer 4

https://www.google.com/search?q=learn+kotlin&oq=learn+kotlin&aqs=chrome..69i57j69i60j0l4.1249j0j7&sourceid=chrome&ie=UTF-8

^Just type "learn kotlin" into Google and click search. Half a million results. You're welcome. Start from top of list and go down. Learn what you can from each resource.