When you run 'firefox -ProfileManager' in a terminal, you should get a window showing a list of your profiles. Select to create a new one, name it something like 'test', make sure it is selected, then click 'Start Firefox'.
When you run 'firefox -ProfileManager' in a terminal, you should get a window showing a list of your profiles. Select to create a new one, name it something like 'test', make sure it is selected, then click 'Start Firefox'.