Migrate from Jekyll
Move static content to static
Jekyll has a rule that any directory not starting with _ will be copied as-is to the _site output. Hugo keeps all static content under static. You should therefore move it all there.
With Jekyll, something that looked like
▾ <root>/
▾ images/
logo.png
should become
▾ <root>/
▾ static/
▾ images/
logo.png
Additionally, you’ll want any files that should reside at the root (such as CNAME) to be moved to static.