Having multiple workspaces can be a great way to keep all of work for different organizations separate and organized.
If you want to add a new workspace click the dropdown menu next to your avatar in the Nav Bar. Then click Create New Workspace.
A window will appear asking you for the name of your workspace. Give it a new name and hit 'Create Workspace'. The new workspace will be added to your list of workspaces in the dropdown menu and you can easily switch between them.