Every lecturer (role) in Brightspace has access to their own personal experimentation environment (Sandbox). You have access to all necessary functionalities, and can try them out without possible unwanted consequences for yourself or your students. The Sandbox is private: only you and the colleagues you have enrolled can view its content.
You can, for example, experiment with new ways to present your content, create new tests for students and discover ways to improve interaction with students. You can also prepare a course in your Sandbox and export it to a public course when satisfied.
Please note: the Sandbox is located in the production environment of Brightspace. Normally only you have access to the Sandbox. You can, however, add other existing users if you want. Only add someone if said person has agreed to it. As soon as a person is added to your Sandbox, the Sandbox will appear between that person's course, after which they have immediate access to your Sandbox.