One of the most important 1st steps when starting out with Box is planning your folder structure. Checkout this article which covers the following points. 

Here are some questions to consider before designing your Box folder structure:

• Who moves, owns, and maintains the content?
• What root level folders make sense for your org? This is typically based on the departments, regions, or groups using Box.
• Does your organization prefer to give users the ability to create and manage their own top-level folders? Or does your organization prefer to own (and control) all root level folders?
• Do your Admins and co-admins need full access to users' content?
• Are different levels of access needed for users, or are groups appropriate?
• Are there any particular security needs around any of your content?

Folder Structure Basics:

There are two basic Box folder structures to choose from: open folder taxonomy and closed folder taxonomy. The taxonomy you choose is largely based on your internal security protocols and workflows.

Folder Structure Best Practices:

Understanding Box’s folder permissions and collaboration features will help you configure your folder structure so your team can get the most out of Box. See the Folder and Subfolder Permissions article to learn more about Box's waterfall permissions.

1. More restricted content should live at a higher folder level.
2. Ensure naming conventions of folder and files are extremely clear.
3. Keep the structure as flat as possible.
4. Every user's "All Files" page will look different depending on the folders they've created and/or the folders they've been invited into.
5. Create separate folders for external collaboration.

To learn more checkout the full article here