You need to register an account and set up your app on GA website first.
Add GA plugin to your project and configure the Game Key and Secret Key for Android in plugin properties. You can find the values of these keys in the app dashboard on the website under Settings.
Add "GA Initialize SDK" action to your loader or first layout.
This should be enough to track basic events, like app launches, playtime etc. If you need to track other things (for example level progression), you can do this too, just add these actions to your game events. For example:
When player starts a new level - GA Add Progression Event Start "Level1"
When player finished the level - GA Add Progression Event Complete "Level1"
Here is the official documentation, but it may be outdated:
gameanalytics.com/docs/s/topic/0TO6N000000XZEyWAO/construct-sdk
You can check if the integration works by clicking Realtime -> Live feed in the dashboard, the messages there usually appear within minutes. Note that you might need to wait for several hours or even days before the data appears in other screens.