Hi guys,
I wonder if you can help? I am trying to build a website using the new word press 3.6 and I am using a blank theme to create it in which I took and learnt from Lynda.com. Now I have created a few websites in the past using the theme but for some reason I am having problem creating a custom menu using menus under the appearance tab.
The steps that I usually take are

1, To add this code in the function file of the wordpress theme

if (function_exists('register_nav_munu')) {
'main_nav' => 'Main Navigation Menu'
2, My next step is to create a ‘menu name’ in menus under appearance in wordpress and then add the menus .

3, my next step is to add this code in the wordpress template and put in the name of the menu that i created.

<?php wp_nav_menu(array('menu' => 'Main Nav Menu')); ?>

But for some reason its not working for me and i have ran out ideas,
so has anyone got any ideas, of what i have done wrong or better ideas of how i can solve the mystery?

Thanks in advanced