Thanks for using our plugin.
You should follow this way
Step 1. At first create a menu from DuoGeek->Menu Manager
Step 2. Create Menu in Appearance->Menu
Step 3. After creating Menu in Appearance->Menu go to Manage Locations And select Menu location with Created Menu name in DuoGeek->Menu Manager
Step 4.Select menu pages in Menu section with your created Menu name in DuoGeek->Menu Manager
Step 5. Go to page section and create a page where you can see options.You need to check Enable Menu Replacement and select where you wanted to show menu and select your created Menu.Go to your created page and you can see replaced menu.