In this article I’ll show you how to create your public website on sharepoint online after we configure our public domain to point to sharepoint online.
Open Sharepoint online administration center and click on site collections, In the first tab click new and select Public Website.
In the Create Your Website page fill in the details of the new website and make sure you select the domain you added from the first step.
Once done, use the browser to navigate to the website.
To edit the page, just click on Member Login link and edit the page