Head over the the bottom left corner. There you will be able to create a new workspace.
Creating a new workspace is the same as the initial workspace creation. Head over to that article to get help.
Once you've create a new workspace you be able to switch workspace in the same area.
Switching workspaces
You'll be able to switch workspace and continue creating Landing Stories.
Signing out
The last option will be to sign out! That's all in the same place.