There is an issue open to add areas, but for now, you have to add them yourself.
https://github.com/NodeBB/nodebb-theme-persona/issues/69
If you just want to change some css, you can use the class that is added to the body tag, and add to the custom css section ike so:
body.page-recent div[data-widget="theWidgetName"] { color: orange; }
kurt-stolle created this issue in NodeBB/nodebb-theme-persona
closed
No widget areas defined
#69
