SambaCard, need AddFund button on CashScreen

Hello, after trying to put SambaCard in action. I decided to stop using Cash and CreditCard payment. I want it this way:

Order > Scan SambaCard > Print Bill > Add Fund > Settle > SambaCard Payment

The resean I want to do it this way because I want to I know how much money a customer spent at my place. Then I can upgrade their card from Standard to Silver or Gold.

Anyone know how to do it? Thank you.