How to use Gradle in Unity

Question

Since I want to add Firebase to my Android Game I want to include Google Auth. But I have the following Problem. I need to add some Code to the build.gradle File but I cant

Answer 1

From Unity v2018.3 onwards, you can add your own custom Gradle build file by simply enabling the Custom Gradle Template property on the Player window (which can be accessed by File > Build Settings > Player Settings > Publishing settings). This generates a default mainTemplate.gradle file for you, which you can edit.

It will be in the location: Assets/Plugins/Android/mainTemplate.gradle

Source: https://docs.unity3d.com/Manual/android-gradle-overview.html