Correct API data and QR code url

I need help to configure the plugin:

– What data should I put in the API credentials? In my paypal account I do not see the fields that you put in the plugin.

You put these fields in the plugin: Live API Client Id, Live API Client Secret and Live PayPal Webhook Id.

In my paypal account, in the NVP / SOAP API integration (Classic) section, these fields appear: API Username, API Password and Signature.

What should I put in the plugin fields? I have placed the following:
Live API Client Id: API Username
Live API Client Secret: API Password
Live PayPal Webhook Id: Signature

It tells me this message: Authentication failed due to invalid authentication credentials or a missing Authorization header.

Another question is that I should put in the field of the plugin QR page url? The url where I put the QR image?

The page I need help with: [log in to see the link]