Setup

Set Preferences on config.xml

1). Set the api key  
<preference name="shop-checkout-android-api-key" value="API" />
         
2). Set the shop-checkout-android-box to false if in production
<preference name="shop-checkout-android-sandbox" value="true" />

Implement Androidx

1. setup androidx for your project by implementing androidx on dependencies in platforms/android/app/build.gradle file

implementation "androidx.core:core:1.0.0"

2. implement Androidx on platforms/android/gradle.properties

android.useAndroidX=true
android.enableJetifier=true

Set Minimium SDK

set the default minimum SDK to version 21 in build.gradle located in platforms/android

defaultMinSdkVersion=21

App Initialization

For App Initialization, add your API Key to the preference on config.xml by inputting the following command below

<preference  name="shop-checkout-android-api-key" value="YOUR_ANDROID_API_KEY" />