Request API access and register applications at https://developers.paydunk.com. Check in the Applications tab to view all of your apps. You'll see each of your apps are given an App ID and App Secret.
Along with the front-end plugin (found here: https://github.com/paydunk/front-end-plugin), use our test.aspx file as your payment accepttance URL to get started with paydunk quickly. Run your transaction as you see fit using the information POSTED from the Paydunk API (starting on line 27). Be sure to update the client_id (App ID) and client_secret (App Secret) values (lines 10 & 11)!
To see this test working, visit http://paydunk-001-site1.smarterasp.net.