Tried pay with a view but was not suitable, so having

Hi Tried pay with a view but was not suitable, so having another look at your membership plugin. With Pay for View had to enter paypal API codes for it to work.
Can find nowhere for this to be entered with membership. And as paypal not popping up when people should buy think I need this info adding somewhere? Customers are just registering not being asked to pay before access.
Only asks for paypal email address.