The process of creating menus in Vanilla template is almost the same as that in Joomla. In Vanilla, the best position to place a menu would be in the mega menu. Mega menu is a feature from the Helix 3 framework. However, you are free to select any position that best suit your site.
To create a menu, navigate to Menus > Manage > Add New Menu. Once you are there, enter the title and menu type of the menu, then save.
Once you have created the menu, head into this menu and click on the 'New' button. This allows you to create a new menu item under this menu.
Next, click on the 'Select' button to choose the Menu Item Type. A popup will show allowing you to select the menu item type.
Once you have chose the menu item type, configure the menu item according to your needs and save. If you want to make this menu item a sub menu of another menu, feel free to select the parent menu item on the right side of the menu item configuration.
Head back to the modules page and create a menu module if you do not have one. Enter the menu module title, select the menu that you configured earlier and the position where you want to place this module. Feel free to configure any other setings if you want.
Save the module and the menu should now display on the configured position and page/s.