When creating a new Developer Sandbox at https://app.box.com/master/sandboxes, it would be helpful to see the "Dev Console" button at the bottom left of the Box dashboard when logging in as the Primary Admin of the sandbox. You can access the Dev Console by navigating directly to https://app.box.com/developers/console, or by clicking a button in the invitation email, but if that button is overlooked, it can be confusing to figure out how to navigate there.