If you installed the demo data follow the next steps
From your WP Dashboard go to "settings" => "reading" and click the "static homepage" option. From the left dropdown choose Front Page page. From the Blog choose the page with the same name as Posts page Save settings and you are done.
You need to create a page that would be the Main Page (for One Page layout) , this page will be the "holder" for all the content you will create
Go to "Pages" add a new page and call it Home & select under page attributes One Page Template as Template and publish the page.
Now go to "settings" => "reading", click on "Front Page Displays" => "A Static Page", then use Home as the "Front Page"