Your navigation bar is the backbone to your app, it is how your users can switch between the different pages you have created.
You can edit the navigation bar by going to the cog settings icon next to the pencil in the top right.
Click on settings cog in top right next to pencil icon
This will bring a drop down menu, select Configure Navigation
You can then:
Enable menu items using the toggle switches
Rename menu items using the pencil next to each item
Re-order menu items using the grab handles to drag and drop
The homepage of your app is the first item that appears in your navigation menu, you can see this marked with the home icon in the navigation menu editor.
Open the navigation menu editor and drag the item you'd like to be the homepage to the top of the list.
To create a secondary navigation please see Multiple list pages.