Fillout and paypal

hi all, i try to setup up a scenario to handle payments from my site.
so i built a scenario where for every new submission in my fillout form (the trigger) i try to create and execute a paypal payment.
i created the app into my paypal account (business)
once i submit the fillout form, my scenario start and pass data to the Paypal step1 (create the payment)
the outbound of creation is

so it looks like some essential parameter is missed.
i can assume that the payerID is corresponding to the ID in my outbound, but i can not figure out where the payment_id is. is the last portion of the URL? if yes, how can i rip the data?

and second question: i was presuming that during the creation of the payment the paypal authentication webpage would appear. is not my case. did i did anything wrong?

thanks