Understanding how to organize your content in Joomla is a key skill.  Sure, you could lump it all together (and that's fine if you have a small site), but generally you will want to use Joomla's Sections and Categories structure to break your content in to a more managable structure.

• Step one: Get a firm handle on Joomla Lingo and learn the difference between a section, a category, and a content item.
• Cory Webb has an excellent article on how How to Joomla website (www.howtojoomla.net) that will help explain this well.  Follow this link to read Cory's article...

• In addition, Barrie North of Compass Designs has a good article titled "Content is King:A Beginner's Guide to organizing content in Joomla "  that you may find helpful.