You can only use the discount for yourself. As an LP (Loss Prevention) policy, you are expected to use your employee discount responsibly. Using it for family or friends for some reason is loss in the company's profit, and you could get terminated if they find out about it.
Your employee discount card is used for only regular priced items; it doesn't work for clearance merchandise. Your regular clearance discount is 20% off, and when there is a floorset at your store, they give you 50% off on three selected items of their choice, usually new items, which are a top, a bottom, and an accessory. You can only get the discount at the store you work at. If you buy something from another hollister, you can go to your store later with the receipt and they give you your discount there. The discount only works for Hollister.
They also highly recommend, or they might even require, that everytime you make a purchase, you use your discount card even if you're not getting a discount from the item. They use this card to track the purchases you've made. They do this because they sometimes get internal theft within the store, from employees, and they need to track everyone there.