If you have a custom menu and all you want in that menu is tabs to Pages you have accomplished that. However, with a custom menu we can display Categories and drop-downs to sub-categories in tabs along the horizontal navigation where normally only Pages tabs are displayed. We can also include Pages and drop-downs to sub-pages, tabs and Custom links tabs in our custom menu as well. If you also wish to display Categories and/or custom links then I have more instructions for you.
What’s critical is:
(1) a clear comprehension of the differences between pages and posts > http://en.support.wordpress.com/post-vs-page/
(2) a clear comprehension of the fact that there is only one dynamic page in a blog for posts and we cannot post to more than that one page. But we can create the appearance that we have posted to more than one page.
We organize our posts by assigning Categories to them. When we publish a post it automatically appears on the running page for posts and also on the Categories pages and Archives pages. Note: There must be one published post in each Category in order for there to be anything to display.
A custom menu allows you to display Categories with drop-downs to sub-categories in tabs along the horizontal navigation where normally only Pages tabs are displayed. If you wish you can also include Pages with drop-downs to sub-pages and/or custom links in your custom menu as well. You are in charge of what appears in a custom menu. You choose the order in which to display any and/or all the foregoing in your custom menu. You choose which to display and which to hide. http://en.support.wordpress.com/menus
If you have difficulty with order then do check the sub-pages themselves to see if you have established a Parent page and child page “hierarchical structure” in the page attributes module. Remove if required. Also remove any “order” numbers you have assigned that may conflict with the order you are creating by dropping and dragging. Or simply change them so they are the same order as you establish in the menu. Establish consistency – problem solved.