Discount code message

[DAGNORAK]

问候,我运行一个折扣code that requires customers to manually add a product that they will be getting as a gift once they spend £50 plus. For the coupon to work they need to add the gift product themselves . If not they get the following message at checkout (see image ) Is there any way of editing this message to add a sentence for example (please make sure to add “item” before checkout for coupon to apply) because the current message is a bit vague and might cause confusion. Thanks

Website : DAGNORAK.myshopify.com