Pay-per-view plugin: API credentials


could you please help - which API credentials should I provide, I need a production page where users will be able to pay in order to see a video - a straightforward process without any user registration or similar...

I opened the developer paypal page and do not know what API should I choose (is it NVP/SOAP APIs? - if yes, then there's a complicated description process (New app - app information questionnaire). In the plugin settings guide you mention that it is a straightorward process, however I struggle to find the place to create an API username, API password and signature).

Appreciate your help as the topic is relatively urgent.