Setting up project for https://github.com/gradle/gradle in IntelliJ 2018.1.3

I’ve cloned https://github.com/gradle/gradle and want to set up a project for it in IntelliJ 2018.1.3. Are there IntelliJ setup instructions for this project anywhere?

IntelliJ complained that I haven’t setup a Groovy SDK for the project, but I don’t know what version of Groovy I should use. I setup a Java 10.0.1 as my Java SDK; will that work? What Project language level should I use?

Thanks.

I just found .github/CONTRIBUTING.md, which probably answers my questions…