Widget attempt, says need a template with sidebar - where is that?

Phoenix theme (the one by FastWP vs. one of the many other themes by the same name!). I tried to add a widget in customize. Says I need a template with a sidebar. I can’t find a template, that affects all pages, anywhere nor can I find an answer in the ten training videos, search, or YouTube. Where or how can I get a right sidebar or a site-wide template so that I can place a widget in the right sidebar? If not that, even a footer widget area might suffice.

It’s better to contact the author. Forum is for general purposes but not for item support