Step 1: Define your Google Pay API version. Step 2: Request a payment token for your payment provider. Step 3: Define supported payment card networks. Step 4: Describe your allowed payment methods. Step 5: Create a PaymentsClient instance. Step 6: Determine readiness to pay with the Google Pay API. Step 7: Create a PaymentDataRequest object. Step 8: Register event handler for user gesture. Step 9: Handle the response object.