form/accept online payment integrate with paypal PaymentsPro

i'm signed up with website payments Pro on paypal and i have no idea how to go about doing this by myself. my goal is to simply have the customer fill out a form for membership and then also make a payment immediately with a credit card, all doing this within my website. Ex. you come to my website [Removed by Freelancer.com Admin] and click the membership button and are brought to that page, and you read what is offered with the membership. therefore have another button to popup a new window and it simply being a form for them to fill out and then pay $30.00 for 1-year membership and then let them know the transaction was confirmed and once processed with the api's and whatnot the form popup window will close and thats it.