Redwood Look and Feel in Site Hierarchy Workbench HTML UI
The Site Hierarchy Workbench HTML UI is now available in the Redwood Look and Feel. Prior to Release 12.2.15, the Site Hierarchy Workbench was available in the Oracle Alta Look and Feel.
Launch Hierarchy Workbench and click on edit icon to add hierarchy flow.

Choose the hierarchy to add

Edit added hierarchy from the edit panes

To view attributes of the site, choose an hierarchy from the list or from the edit pane

Steps to Enable
You don't need to do anything to enable this feature.