If you connected a parent node, you will be able to add child nodes only after your parent node adds you as a child node. Prior to connecting a child node, make sure that it has added your node as the parent node.
To connect a child node:
The Connect to child node window opens.
The window will display a description of the certificate and indicate the organization that issued it and its FQDN.
The child node is added and displayed on the Settings → Hierarchy → Structure tab. This tab also displays the descendants of the child node. You can view the incidents of your child nodes and their descendants.