You can have different menus on the posts and pages on your website simply by activating a plugin.
Anyone can make his website by registering his domain name and then subscribing to a Managed WordPress plan which can be enhanced with free plugins available in the WordPress plugin repository.
This lesson is on a new WordPress plugin that allows you to set different menus on posts and pages on your WordPress site.
Simply install-activate the new WordPress plugin called Different Menu in Different Pages and Posts. Once activated, you would be able to set a specific menu for specific posts and pages from the post-edit screens where the plugin adds its meta-box.
Yes, you will need to first create a menu from the Appearance->Menus screen, save it and then it can be chosen for selective posts on your website. The menu you will choose will be displayed on the menu location of the header or wherever you have the menu location. On other posts and the homepage, the default menu will be displayed.