The project has been coded in kotlin, so you should install the kotlin plugin (only if your android studio version is lower than 3.0) to run it.
The following kotlin documentation explains how to install it :
The Kotlin plugin is bundled with Android Studio starting from version 3.0. If you use an earlier version, you'll need to install the Kotlin plugin. Go to File | Settings | Plugins | Install JetBrains plugin… and then search for and install Kotlin. If you are looking at the "Welcome to Android Studio" screen, choose Configure | Plugins | Install JetBrains plugin… You'll need to restart the IDE after this completes.
Now, you just have to launch the project on your device.