great plgin

hi just installed it
i cant understand a few thing

if i want to make 1 post for free and 5 post with charge

how does the user register ?

when i try to choose the 0$ pack it bring me to paypal

how do users register where is the registration form

does this plugin has a premium version i willing to buy

thanks

http://ww.wp.xz.cn/extend/plugins/wp-user-frontend/