First month free promotion

Hi,

I have two membership types. Free and Subscription. There are two sign up frees for the subscription. A monthly fee or a yearly fee.

My site is going to be launched today, and I’d like to offer people one month free subscription.

I figure I can add a subscription rule that the first 30 days are free, but when will the membership plugin ask the person to make their first payment, and when do they have to process that payment via paypal?