The step hierarchy is also known as the object list. It is a tree-like structure that helps the software decide how to link up objects and some of their parameters through a parent and child relationship.

     

Meaning of each icon type:

• White - layer exists in the default state and has not been modified
• Blue - layer exists in the default state and has been modified
• Red - layer does not exist in the default state

A blue arrow indicates a child object has been modified. Expand the tree to find the modified layer.
The grey and blue colors are also used in the Object Properties window to display default and modified properties respectively.

From the Step Hierarchy:

1. You can see object relationships by clicking the arrow beside parent objects.
2. You can show/hide the children by clicking on the arrow. Tip: Alt+Click the arrow to Expand/Collapse All Children.
3. Child objects will be below and indented to the right of its parent. When a parent’s arrow points to the right the children are hidden.
4. Right click the parent/child to use other available options e.g. copy, duplicate, cut, delete, isolate, hide and unhide.
   
   Tip: you can also quickly duplicate an object by pressing shift + gizmo drag while moving an object in the Scene View.
   Tip: you can multi-select objects and "parent to new empty". This will add the selection to a new empty object, for easier grouping.
5. Right click context menu also works in the empty space in the Step Hierarchy, it will show context options that are not node-specific, like expand and collapse all.
   
6. Select/Click on the parent or child to edit its properties in the Object Properties window.
7. Finally, you can see triangles count/object count in the step hierarchy.

Symbols meaning:

• ▲ - The total amount of triangles in this node and all of its descendants.
• ⌗ - The total number of child nodes of this parent node.

Here is how to select parts of an object in the Step Hierarchy.