Click on your account profile in the top right-hand corner. You will see the option for "Points Submission Form" there and you can submit photos of your receipt to earn points. It takes about 24hrs for them to be loaded into your account.
To Redeem Your Points
You can see how many points you have by clicking on the "rewards" button on the bottom left of any screen. Once you begin to check-out, you will be given the option to apply as little or as many points towards your purchase.