Hi Scott,
which AWS region did you select in CAL for the deployment? I'm asking because the AWS console only displays resources of a selected region. Once you logged onto the AWS console you would need to select the region in which you deployed the CAL instance. The setting can be changes on the top right corner which a drop down box.
Simply select the correct region and you should be able to administer the instance and add a new volume to it. Please note, that the cost forecast in CAL does not consider the storage and IO costs for this new volume as it is unknown to CAL.
Regards,
Hannes