The shopping list can be found in the Nutrition section of the app. Click the shopping cart icon at the top-right to open the shopping list. Next, choose the period for which a shopping list should be created. You can use the app in the store and mark the items which you have already picked up. Alternatively, you can print the shopping list and bring the paper version to the store.
If you need information about printing resources from the app, please check this article.