To turn points into a reward, you need to log into your account on your site, then click on the launcher to open the rewards panel.
Next, click on All rewards.
If you don't have enough points to redeem, you'll see a progress bar on the right, next to the reward name.
If you do have enough points, there will be a Redeem button.
Upon clicking redeem, you will be taken to a page that shows the coupon code with a button to Apply code which will automatically apply that coupon code to the checkout.