Recurring Billing

For the life of me I can't understand how to set this up or understand the help files on it.

All I want to do is have a product then when a customer purchases it, 7 days before it is due again the following month, the customer is sent a new invoice for another month and a copy of it is sent to me.

I then monitor my bank account as I already do to ascertain if they have paid it or if they pay by Credit Card then they can log in to my store and pay the invoice.

I don't understand all this Pay Day, Recurring Duration etc. in the recurring plan or the Addon Settings of:

Number of attempts after order failed:

Next attempt if order failed (days):

The different statuses

The different notifications etc

Can anyone PLEASE help me out in very simplistic terms what I need to do to simply be able to automatically invoice a customer every month 7 days before it is due?