Setting up an organizing a navigation menu on wordpress is pretty simple. This tutorial is short but it will show you how to do it and assign your menu to any of the navigation menu area. You will need to have your pages and categories created beforehand.
In your wordpress dashboard, navigate to appearance > Menus.
On the page that opens up give your menu a name, maybe something like top or bottom menu, then hit “create menu”.
Once you have created your menu, the next step is to add your pages and categories. On the left hand side, you will see a pages section and a categories section. Check each page or category you want add to your navigation menu and hit the “Add to menu” button.
Now you need to organize your pages and categories, you can drag and drop them to rearrange them, you can also create dropdown menus by placing a category or page slight to the right, underneath another page or category.
Once you have added and arranged your menu items, select a display location, usually primary or secondary.
Hit the “Save Menu” Button in the bottom right corner and your menu will now be set up! If you are using a theme that uses two navigation menus, follow the above steps to create a secondary navigation menu and assign it to the other area.