PayPal Chained Payment API Set Up

Hi there,
I am trying to set up PayPal chained Payments so I can collect a percentage of sales made by sellers on my marketplace site.

I have completed the forms but PayPal have said:

"I'm afraid i cannot see any additional steps / URL's etc. in your app submission to enable me to test. Could you just put the information in the 'comments' section and then click 'Resubmit for Approval' please?"

CAn you help me with given them what they require please.

If you need admin access to the site please let me know.