You are not in a rare situation, and many consumers who are new homeowners wonder this same thing since the mortgage and home closing process is really crazy and then they don't know what to do or who to pay to make their first mortgage payment. Even more complicating, many times lenders will actually 'sell' the servicing rights to your loan and it can take some time for you to get your mortgage payment coupon books. It's also likely that they will offer you a discount or an incentive to do automatic e-payments every month.
For now, though, you can call your lender and request the coupon book so that you make your first payment on time. Trust me, these days they will be pleased that you are looking to make a payment and that you are being diligent about making payments on time.