Once you have proceeded to the payment options at checkout for your order, any available Max Dollars will show at the bottom of the payment page. Clicking "Use reward points" will apply these to your order. You can then proceed to your next payment method for any outstanding balance owing.
Any available rewards can be found on your account page here. Simply apply your unique reward code in the promo code field at checkout.
Please note: Max Dollars cannot be used to purchase Max Gift Cards.