The Storefront theme is definitely one of the better free themes. That makes sense because it was developed by the creators of WooCommerce.
The functionality of Storefront is a bit limited. However, you can expand the functionality by installing additional plugins for Storefront, which you have to pay for. Let's first take a look at the changes that you can make by default.
After activating the theme, it will add additional menu items to the Appearance menu in WordPress. Here, you'll find several shortcuts for additional possibilities. WooThemes is a commercial company after all, so there are plenty of links here for more options, which you have to pay for.
Whether you click on the link to Configure menus or Open the Customizer, in both cases the WordPress customizer will be opened. Since WordPress 4.3, you can change your menus from within the customizer, but the old function using Appearance | Menus is still available:
Just navigate the various options to change...