Questions about the plugin | WordPress.org

Hi,

I am new to the plugin, trying to figure out how it works.

1. Is the submission done automatically or manually through this URL: https://api.indexnow.org/indexnow/?url=url-changed&key=your-key?
2. When setting up the plugin says ‘You only need to select one search engine because with the IndexNow protocol, the selected one will notify the others’. I am confused: Is Bing API and Yandex API eventually needed? Or the IndexNow API Key is enough?

Thanks.