Where and how can I add a menu item?

All the menus are listed at http://www.tanchan-cpa.com/admin/build/menu/list

Keep yourself away from the following Menus:  Administration menu, Navigation, Latest Updates, Login and Secondary links.

The first two menus are the system menus, change anything inside might cause the site down.

Latest Updates is updated by the system automatically and don't change anything inside.
Login is the link to the login page, don't change anything inside. It might lock the users outside and cannot login.

Secondary links is empty.

Now about the Main Menu, you can go inside to have a look. Unless you are very sure about what you are doing, don't change anything inside. The main Menu are almost the key of the site. All the main services of the site are listed there. PLEASE READ http://www.tanchan-cpa.com/how-create-web-page-under-main-menu-295.html FIRST.

If you want to change the position of the menu item of the top Main Menu, then you come here: http://www.tanchan-cpa.com/admin/build/menu-customize/primary-links, drag the arrow beside the menu item you want to change and move up or down to the location(Under the menu items) you want to put, then you click Save.

You can play with Archive Menu and Resources Menu. Please read this one first: http://www.tanchan-cpa.com/how-add-archive-year-such-2010-305.html. At the Archive Menu page, Just like Main Menu, you can drag and move the arrows beside the menu item to change the position  and then save.

For Resources Menu, please don't change the menu items under here if not neccessary. Instead you can put a page under the Forms, FAQ, Knowledge Base, Newsletter. 

If you really need to add a menu item at here, just create a page, click the menu settings and select Resources as the parent item. And input the Menu Title that will appear at the Left menu. And save it.