How to limit a Flat-Rate shipping on an order?

Hey Guys,
I’m trying to set up my client galleries so that there is a Flat Rate Shipping charge on their total order. Whether it’s one or two prints, or a Print Package. How do I make that happen?
In the ‘Shipping’ set up, there is:

  • Per-item Shipping
  • Minimum Shipping for this Package
  • Maximum Shipping for this Package

Should they all there be set to a same amount? (e.g.: $15)
Or should ‘Per-item Shipping’ be set to '$0", or some different combination?

Look at the top of the Pricing page and then set all other pricing to $0