At Settings > Shop settings you can close your shop. Your customers will see a message to come back later. Meanwhile, you can fill your shop with categories, products and pages.
Alternatively, you can deactivate the shopping cart. You can set this also at Settings > Shop settings.
For indexation in search engines we advise you to not close the shop, but to deactivate the shopping cart. When a shop is closed, it will not be indexed in search engines, or pages that are already indexed will be removed from the index.