Create a database and payment system

Please I sincerely ask for help. I swear I have searched both Google and Kodular community for help and I have always been stuck at this point of my app development. Let me break down the issue.
I created an app that sends data through a QR code scanner. The issue now is that I want the data of each user to be saved online maybe in firebase or airtable. I managed to configure the airtable but how to retrieve each users balance and profile details after each login is now a problem. I also want to add a payment system. I found out PayTM is only for Indians and thats the only tutorial for payment integration I saw online. Please I need help with PayPal or PayU.
I will paste the blocks below,


These are the screen 1 blocks that can be used to login.

This is the home screen where I would like that balance label to be loading the users balance after each login and upload the latest balance after each transaction.

Truth is that I don’t even know where to start in the payment integration. Please anyone who can be of assistance. I would really appreciate it so much. I will also paste the aia file here so anyone who can make an edit to it can. I really appreciate your help in advance as I am patiently waiting. Thanks

code.aia (69.3 KB)

I have changed the catagery to #discuss. Which is relavent to the topic.

You can only use the #marketplace when you want to sell or buy service/apps in Community

Thank you so much. :heart_eyes: :heart_eyes: :heart_eyes: