After you've added nodes to your hierarchy, you can assign accounts to them. Accounts are initially assigned to the unassigned node, but you can move them (or assign them) to different node levels.
To move an account to a different level:
Did you know? You can also edit descriptions for any node, account, or service using the Tree Builder screen. Select the node you want to edit, and then click Edit Descriptions. Make your changes or additions, and then click Save. (You can also edit sub nodes using the same screen. If you don't see the sub node you want, try clicking the plus (+) sign to expand the branch.)