I apologize in advance for this question, I don't really know anything about SharePoint and a site was just kind of created for us and dropped on us without any training or explanation. I'll try to describe the issue as clearly and succinctly as possible without knowing the correct terms (which has made trying to navigate the help section unproductive).
Our K-12 school district wants to use Sharepoint as a video file storage solution. A site was created for us with our campuses individually listed under elementary, middle, and high school sections, which is how they're listed on the Sharepoint start page and the Campuses dropdown menu on the navigation pane at the top. When someone uploads a video and edits the properties, there's a dropdown list titled Campus where each school is individually listed as they're shown on the start page, and adding a campus there makes it show up on the relevant page.
We need to add a new section called District Resources with a subsection called Eanes ISD. I've had no trouble adding it on the start page, and it shows up under the Campuses navigation menu at the top, but apparently this is not what populates the Campus drop-down menu under Properties.
So I guess in a nutshell my question is how to control what metadata is available under the Properties section of the Details pane.