Hi Travis
This had me totally confused too. The post from OldRadioGuy gave me a clue.
Here is what I did after creating a new Catalog
1. Opened a contact sheet (any one will do)
2. Next to the folder icon at the top of the column on the left is a new icon which looks like a small sub menu list in graphic form
3. Click on that
4. I went to the Catalog Menu and chose Scan to catalog
5. I selected a whole bunch of folders
6. Pressed Start button
7. Waited until the scan was complete
8. Below the section which allows quick search there is a section called Tasks
9. That section shows me 5 rectangles
10. I click on the bottom one (The catalog I created)
11. It is called: "Catalog Image Preview"
12. I also have a new Tab in the contact sheet tab set called: "Search"
13. If I click on that Tab I get my whole catalog OR the ones which match the search criteria I have selected
My Image count for my catalog is 16,740
I am still exploring the search options. The good news is that it uses all the contents of the lists of keywords I had already created for selecting and tagging (IPTC) so it is very powerful