Go to the store's website. Usually, they have a "search" feature. Search for what you want. Then hit the "add to cart" button. After you get everything you want, click "cart". This is usually located in the upper right of the webpage. It'll ask you if you want to create an account or proceed as guest. You don't have to create an account, but if you use the website often, consider making one. Regardless, simply input the information and follow the instructions. Be sure to use a valid email, they will send confirmation and tracking numbers to it.