(These instructions were tested with Android Studio version 4.2.1)
Open Android Studio and select File->Open... or from the Android Launcher select Import project (Eclipse ADT, Gradle, etc.) and navigate to the root directory of your project.
Select the directory or drill in and select the file build.gradle in the cloned repo.
Click 'OK' to open the the project in Android Studio.
A Gradle sync should start, but you can force a sync and build the 'app' module as needed.