1. Open Settings -> Plugins -> Browse Repositories -> "Code Review for IntelliJ IDEA" and install plugin
2. Restart Intellij IDEA for changes to take effect.
3. Open Settings -> Other Settings -> Code Review and set your Crucible server/username
4. Open Code Review toolwindow
5. Review with pleasure )

Setup IntelliJ plugin SDK (see https://www.jetbrains.org/intellij/sdk/docs/basics/getting_started/using_dev_kit.html)