This page demonstrates the Login box, HTML, Calendar, and News content types.  
The Login box can be configured in Site Preferences in Admin (for example, to disable the ability for users to self-register).

Calendar items and news articles can be edited by clicking the red bugs you see next to the main titles.

Click Edit Site at the top of the page to edit or delete sub-sections (like News or HTML), including these notes. Content can be added by clicking Include Content at the bottom. 

See our tutorials for more information.