Your files are organized in folders, placed under the "My Files" button on the Sidebar > Storage.
Each folder gives you the visibility options for you to choose from,
- Everyone
- Only Me
- Shared
"Everyone" means everyone who is a part of the workspace will have access to that folder.
"Only Me" means no one besides you has access to that folder.
As for "Shared", this option allows you to pick which collaborator you want to have access to that folder.