Here is a step by step guide to add a coupon code - Refer to the steps and images with red circles below.
After logging into your account,
Step 1: Click on the Payments tab on the selection menu
Step 2: Enter your coupon code and click "Add"
If an error message appears and you are not able to add the coupon code - it may be because you typed it in wrongly, or that it is expired.
Step 3: View your coupon codes under "Applied Coupons"
The coupon discount will be automatically applied when you book a service.