To set up your network of sites, click the Sites tab.  Highlight the "Network" node.  

Note: Node refers to the level in your site hierarchy.  Each network has a different node level based on their sites and locations.  Refer to site hierarchy best practices for guidance.

Click the green plus sign in the Sites task bar to add a new network node.  You will be prompted to name the Network. Click OK.

Click on the new node created and repeat this process until you have created your desired network hierarchy.

Multiple site can be added to a single node.  See below.

Both site and node level names can by changed by right clicking and renaming, or selecting the edit button seen here as a paper and pencil icon in the Sites task bar.  Remove any sites by clicking the red X located in the task bar as well.