First, you add an item to your cart by klicking "+ Add to cart". Then you press "view cart" in the top right corner. In the cart, you simply press "Checkout now", and proceed through the checkout. Hope you understand. Otherwise, you can always use the Live help chat in the bottom right corner, Mark and Eric are very nice and always help out.
If you want to email them, you can use Sales@PenguinMagic.com and CustomerService@PenguinMagic.com.