After first build of the project, there will be no module that can be run. Please find the "Gradle" tab on the right tool bar, click it to show the Gradle script list. Search gt-sdk -> :gtrsdk -> Tasks -> build -> assembleDebug and run it.
From now on you can find a default script called gt-sdk:gtrsdk[assembleDebug] which is used to build the jar file. And the jar file is located in gtrsdk/achievements.