How to prepare an environment for Kotlin?
Download and install IntelliJ IDE. You can start from IntelliJ Community version. It can be downloaded here: https://www.jetbrains.com/idea/download/
Install or unzip the downloaded IDE and start it. Welcome to IntelliJ IDEA window appears:
Click the button "New Project". New Project window appears:
In the left-side list select Kotlin and enter a new project name e.g FistApp. Then click "Next". You can choose other project parameters but by now leave all by default values:
IntelliJ IDEA opens the newly created project (you have to wait while all dependencies are downloaded and the project data are indexed):