Once you have published Articles in a Category you will probably want to create a Menu item to show all the articles in that Category

Here are instructions on how to create a Menu item (or link) for a Category

1. Log in to full administrator login
2. from the menu along the top select menu and mainmenu
3. Click the New icon (top right)
4. Click the Articles link (so it expands)
5. Click the Category Blog Layout link
6. Type the text you want to show in your menu in the Title box (e.g. About) - keep it short so it fits on your menu button
7. Select the Category from the Category list pull down on the right hand side
8. Select other parameters on the right (like whether you want to show the Category Description / image and how many articles to show with Intro text and columns etc.
9. Click the Save icon (top right)