The last step before you can start working with the new theme is to create your menu. Go to Appearance > Menus and you will see a panel where you can create new menus. Create one, add your created pages to it (from the left side panels) and save it. Now set the locations for the menu that you just created. The main menu will probably be set at Main Menu, Responsive Menu, and Scroll Menu.
If the responsive menu is not working you probably didn’t set menu locations. Please check the image below how to set menu locations: