After you add items to your basket, you'll be shown a basket summary page before you check out. To add your discount code, simply click on 'enter discount code here', type or paste your code into the box and click 'Submit'. Your total will then update to show any discounts applied.
Please note, discount codes will not usually work on dated activity bookings or cash vouchers. All discount codes will only be applied to the main price and will not be applied to any extras, upgrades or delivery prices.