in general only edit content between and The PHP code above and below control how the pages are displayed and if there is a problem then the entire page will look very weird.
Adding news and events
Go to /includes/news.txt
Add a list item at the top of the list. It is essential that you use the exact syntax (please copy paste): <li class='news'> your news here </li>. Any list items within your update should not have that class.
If the news item is long please break it up by inserting <more> after a short snippet (please don't use <more> between any set of HTML tags (other than the li tags you use for the item)
Save the file and go to the Imager website to ensure that nothing has broken.