As I understand it, you just have to check the site regularly to see what tips are on there. Then you can place an order for any tips you see on the site. Yours will appear when they are made, but if you don't want to wait, you may order someone else's tips and then Bert will remake them for that person. Likewise someone else might order your tips and then Bert would remake them for you to order at a later date. Once you place an order your custom order is complete. You will be removed from the beta team, and you will have to wait until the grand opening (which will happen once all the Beta Team people have placed their orders) to place your next order.