Creating new spaces is easy. Click on "Change space" dropdown in the top toolbar. You will see a list of Spaces you recently visited (up to 5). At the bottom click "Go to Space list"
Once in the Space list, you will see all Spaces you are a member of. Click on "New Space" in the top right corner to create a new working environment.
You will be asked to give your new Space a name. It has to be unique within the domain.