NFC is not used in App Inventor

Hello, for a project of mine I want to make a transaction when the NFC tag detects anything (a typical tag like credit card, debit card, city bus card) and reads it. My NFC device works, because it works in other applications. But I don't know how to do it in App Inventor.

At first it works on Screen1, Read Mode is off at first. When a button is pressed, Read Mode opens. Then I want it to process when it finds something, but I don't understand which block to use, can you help me?


What you can do with NFC NearField

Normally we have a project, it will be a design, so it will not have a function. The project will be done in partnership with the city municipality. The city bus cards will be scanned on the phone and they will be matched with each other. It will be something like that, but that's not my goal right now. I just want it to switch from Screen1 to Screen2 when the transaction is made. That is, when we scan anything for example, it should also perform the transaction.