You can create KorGE applications with any editor of your preference that supports Kotlin. I suggest you to use either IntelliJ IDEA Community Edition or IntelliJ IDEA Ultimate. If you can afford it, the Ultimate version has a lot more of features, and it is super sweet if you plan to do fullstack development using Kotlin.
I suggest you to configure IntelliJ IDEA with:
KorGE uses gradle as build system, and the only special requirement to build KorGE is any supported Java JDK.
The easiest way to get started is to download the template project that includes a Gradle 5.1.1 wrapper, a preconfigured build-script, and a small main and a test:
To know how to configure the gradle plugin by yourself, check the Gradle Plugin section.