Those info boxes are blocks used by Postnuke... Postnuke is a PHP based (programming language) content management system.
You cannot create those types of auto-filled info boxes with HTML alone. PHP is used to fill the boxes with content that is stored in a MySQL database.
You can create boxes and fill/update each one manually with HTML.
If you see code on your site then you are not using the right steps to add the code. Click on the Code Editor tab in the editor first. All of this is explained in the stickies at the top of the Copy/Paste forum.