Kristófer Andersen Can you pinpoint any particular line or place which you don’t understand?

Everything in this file is pre-written by Unity, and we should not touch that at all. All we need to do is just add the dependency at the bottom.

dependencies {    
    implementation fileTree(include: ['*.jar'], dir: 'libs')    
    implementation 'com.android.support:appcompat-v7:28.0.0'
}

Apart from this, everything is prewritten by Unity.

I can explain each and every line but for that, we need to go in details of Android.