A tiny hello, in everyday words
One screen. One button. When the button is tapped, the text becomes Hello. That is the whole first Kotlin app in this school. File-by-file work waits for Stage 5 so you are not copying a cathedral.
Stage 5 language
You do not write Kotlin in Termux on day one.
Kotlin is the language Google pushes for Android apps now. It lives in an IDE such as Code on the Go. The job is screens and buttons, not print and input. Stay on Python until those files feel ordinary.
How it relates to Java
Same neighborhood. Older examples often speak Java. New official material often speaks Kotlin. You do not learn both on the same afternoon. Pick the example your IDE gives you and stay with it.
If you are curious anyway
play.kotlinlang.org lets you try Kotlin in a browser without the heavy IDE. Treat it as a museum visit, not homework.
Next step
Java still shows up in menus. Knowing the name is enough for now.