How do I make my site publicly available?

Go to Site Info.

Site Info tool highlighted in the site Tool Menu.

Select the Site Info tool from the Tool Menu of your site.

Click Manage Access.

Manage Access tab highlighted in Site Info tabs..

In the General section, select Anyone (including non-logged in), and then Update.

This will allow anyone (including unauthenticated users) to access the site, either through the Site Browser or via a URL link to the site.