All new subscribers are given a choice immediately after checkout (don't close out the browser window too soon!). You will be presented with 3 boxes/missions to choose as your first box. One of these options will be the upcoming box/mission as long as we are not sold out of it. The three options you see are all available. If you make no selection, then we will send you the upcoming mission if in stock. If not in stock, we will just pick a past mission at random.
Please don't hesitate to reach out to email@example.com if you have any further questions.