Create an account. This can be done by clicking on the "Login" prompt at the top of any page. If you've already created an account, then you're already set.

Login and make a purchase. This can be done by clicking on the "Login" prompt at the top of any page. Points are added after purchase. These points can be redeemed for future purchases.

Add item(s) to cart and select the "Redeem Loyalty Points" option on the first step of the checkout. The option to save the points for a future purchase is also available.