This dialog is asking if you want to import existing settings from a previous installation of IntelliJ IDEA.

The first time you start it up, you'll see the prompt indicating that the application has been downloaded from the internet. After the application has been copied over, you can double click on the applications directory icon and then you'll find that the application is immediately available to start. To install IntelliJ IDEA on Mac, just drag the application package into your applications directory. However, IntelliJ IDEA has had support for JUnit 5 for quite some time, and the latest v2017.3 provides even more goodies inspections and quick-fixes to make it easier for you to migrate your JUnit 4 tests to JUnit 5. I've already downloaded the community edition to my desktop and I'll open the DMG file by double clicking it. The JUnit 5 testing framework was released on September 10. There are two links for the ultimate and the community edition. You can download it from this screen at /idea/download. The IntelliJ IDEA installer for Mac OS is a DMG file.

Intellij for mac 2017