Navigation Bar

Any UI image or panel with a NavigationBar component on it is itself a Navigation Bar. The UI Image, if any, is entirely up to you -- often it's a horizontal line or similar image.
The Navigation Bar should be a child of the Northstar Screen Overlay.
The Navigation Bar will handle tracked objects. Other elements can be added to customize the bar for your project, including adding additional logic to do new things specifically for your project.

Create a Navigation Bar

Open the Northstar Menu: GameObject/Northstar/Create Menu
Click any of the Navigation Bar options to import one into your scene. If the scene doesn't yet have a Northstar Screen Overlay, then one will be created. The Navigation Bar will be a child of this object.
If you already have a Navigation Bar in your scene, you can replace it by selecting a new one from the Northstar Menu.
These objects have a NavigationBar component on them.


Northstar Overlay Settings

A Northstar Overlay Settings object is required. This is the Scriptable Object which determines how things appear on both the Navigation Bar and also Screen and Edge Overlays. Your Navigation Bar prefab (like the ones shipped with Northstar) will have this assigned.
When you insert the Navigation Bar into the scene using the Northstar Menu, the Northstar Overlay Settings will also be assigned to teh Northstar Screen Overlay object.

Visible Angle

This value determines the total angle, in front of the player, that is shown on the Navigation Bar. A value of 180 degrees will include 90 degrees to the left, and 90 degrees to the right of the players forward direction.

Fade Angle

Icons can optionally fade as they get close to the left or right edge of the bar. These values determine at which angle away from the player forward the icon will start and finish fading.
If the second value is greater than 1/2 the Visible Angle, then icons will travel beyond the Visible Angle of the bar -- beyond the left/right edges of the UI image element.

Evergreen Objects

These are objects which are always on the Navigation Bar. They are not tracked objects, but rather element which may or may not move with the player, and generally are things like cardinal directions or vertical tick marks.
Evergreen Object prefabs should have a Tracked Target Overlay on them, which controls how the object is handled by the Navigation Bar, and allows the object to override specific values. Visit the Tracked Target Overlay page for more details.
Objects being tracked in the scene, such as enemies or points of interest, also have a Tracked Target Overlay component on them. Those which are in the Evergreen Objects list are always included in the Navigation Bar.
You can remove Evergreen Objects with the red "X" button, and add new ones by dragging the prefabs into the object field at the bottom of the Inspector.