Where to learn kotlin best

I don’t want to learn kotlin but my sister wants some book for it. I had the idea to learn it in an online course but I have no idea. I would really appreciate it if anyone could help me find the best way.
Great thanks in advance

Hi @j.goergens17! Welcome to the forum.

It’s awesome that you’re wanting to learn. It’s hard to say what resources are the best since everyone learns differently. There’s a list of resources available on the reference page.

It lists tutorials, books, training and more. A lot of it you can do online in your browser. Here’s one of them Kotlin By Example