Is it ok to use Java packages for organizing Kotlin code? Or does Kotlin have its own "package" concept? I'm not very sure of what to click (It's AndroidStudio)

packages are the same for Java and Kotlin. clicking "package" will work just fine

That's great thank you

You can use packages in the same way as Java but in Kotlin they don’t need to reflect the directory structure. In fact the Kotlin language convention should be to start the directories tree after the common package prefix: https://kotlinlang.org/docs/reference/coding-conventions.html#directory-structure