Page not found error 404

I seem to have deleted my ‘welcome’ page – at least I think that is what I have done. ie when I return to my site from the dashboard I get the error message

Not Found, Error 404
The page you are looking for no longer exists. Perhaps you can return back to the site’s homepage and see if you can find what you are looking for. Or, you can try finding it with the information below.

I’m using the Prose theme on Genesis framework.

Any help would be much appreciated,

Thank you (Newbie!)