How do I register Fundraising Plugin with Paypal?

Hi there,

Can someone please explain how to register Paypal API credentials. I've gotten as far as filling out the username, password and signature fields. However I'm a bit stumped about how or why I have to register the application with Paypal to get an application ID.

The fact that the link in the plugin takes you to a site that no longer exists doesn't help. The donations that I've received are showing up in my paypal account but not registering on my website. How do I fix this?