The Navigation Menu is placed under the Build section of your app. It allows you to manage the colours of the Top Bar, Navigation Bar & Top Right Menu Navigation Bar of your app.
Top Bar
You have the option to customize the background color of the Top Bar and the color of the title.
Navigation Bar
You have the option to customize the background color of the Navigation Bar and the color of the menu page link.
Top Right Menu Navigation Bar
You have the option to customize the background color of the Top Right Menu Navigation Bar and the color of the menu page link.
The Design section allows you to choose the colours and to show/hide the share button for your app.
The Layout section allows you to choose the style of your Menu Layout of your app.
You can choose between the Drawer Menu and the Bottom Tabs Menu.
Under the Drawer menu layout, you have the option to align the text of the menu to the left or center.
Please Publish your app once you have made the changes, so they get reflected on your mobile app successfully.