Your Workspace is where scripts are saved that aren't associated with a Client or Campaign
When you use the "Create script" button on the side menu to get started with your script, the Script is automatically added to Your Workspace.
If you navigate away from the Script before adding it to a Client or Campaign you can to return to it by visiting the Library and checking the "My Workspace" area at the top of the page.
It is also likely to be visible in the Recent Scripts area of the Dashboard.
It's not possible for any other Studio user to access scripts in Your Workspace.
You can add the Script to an existing Client or Campaign from the Script options menu. At which point it will be removed from Your Workspace and all Users in your Team will be able to access it.