To add a page break to your content items, simply type "{mospagebreak}" in your content window at every point where you want to start a new page on long content items.
For your Categories-->Content question, you might try doing the following:
1) Go to your admin site.
2) Click "Site->Menu Manager->Main Menu"
3) Click "New"
4) A list will pop up with choices for what you want to add to the main menu. The option you want to select is "Content Category" - don't select "Content Category (Archives)".
5) On the next page, select the category you want, parent item, and access level, and then click "Save".
6) Publish your new menu item on the "Main Menu" admin screen.
You might also be interested in trying a "Content Blog Category" in step 4. Check it out and see if you like it better.
Let me know if you have any more questions. Good luck!
