1. Log in to the Joomla administration area.
2. Click on the “Menus” option on the top menu and then click on “Menu Manager”.
3. Here you will find all the available menus on your Joomla site.
4. Click on the menu you want to customize.
5. Click on the “Menu Item” option on the top menu and then click on “Add New Menu Item”.
6. In the “Menu Item Type” section, select the type of menu item you want to add such as a menu link or a category list.
7. Enter the “Title” and “Alias” of the menu item.
8. Customize the “Menu Item” and “Advanced” options based on your requirements. You can choose to add an icon, description, or parameters to your menu item.
9. Click on the “Save & Close” button to save your changes.
10. Preview your menu item to make sure it looks and works the way you want it to.