From the menu, choose the 'Build Agents' item
You will see a list of the existing Build Agents, if any.
To add a new Build Agent, click the 'Add' button
To edit an existing Build Agent, click the 'edit' link to the right of the entry.
You will be prompted to enter or edit the Build Agent URL and Description:
Be sure to enable the agent by checking the 'Enabled' checkbox.
After you save your changes, verify that 'Enabled' is true. If it is false, most likely Continuum was unable to ping the agent. Consult the log file for additional information.