How to insert line breaks in views global custom text field?
With HTML not allowed, you don't allow line breaks.  You would need a &lt;br /&gt; element to render a line break, otherwise it will be one big paragraph
If you have it set up the way you want, and all you want to do is add the /n to the output of a field:

Add a Global Custom Text field (make sure it is below the field you want to add the /n to).
Insert the token under Replacement Patterns for the applicable field.
In the text box, add the /n after the token.