Regarding the OP's actual question...
If your catalog suddenly takes much longer to load than previously (and you didn't do something that would obviously cause this like increase the number of images in the catalog by an order of magnitude) then try repairing it or restoring from a recent backup. If neither help try reinstalling and installing 8.3.2 (including resetting preferences per
this KB article). If that doesn't help and you purchased your software from a value added partner then call them up or visit their office (bringing along your catalog if practical) as that's what they are there for, or if not then open a support case at
https://www.phaseone.com/en/SupportMain.aspx and someone will reply within 24 hours (usually much faster).
If you want to organize your catalog in some useful way then you'll want to either
- Organize the files into useful folders on the hard drive and then import with files into the catalog "in place" (versus moving the files into the catalog itself) and use the folders hierarchy (right click on the Folders section and select "Show folder hierarchy")
- Add metadata such as caption information or keywording and use filters or smart albums to provide access to subgroupings thereof
- Use the Date option in the Filter (click the "..." drop down in the top right of the filter area, select "show/hide filters" and select Date if not already present) to pull images up by date.
You can select multiple overlapping criterium in the filter by holding option when you click the second and subsequent criterium. So you could, for instance, show up on the Red tagged images from 2015 with a keyword of "People" shot with a Phase One camera.
Learning new software is always frustrating. Especially when it is software which is built for users (pros/enthusiasts) who value ultimate quality, flexibility, and power-once-youve-mastered-it over initial ease of use. Keep at it.
Phase One Catalog system is only in its second generation of refinement having been introduced in version 7 not so long ago. I suspect it will continue to improve in future iterations. But if now or in the future you decide the catalog solution in C1 is not right for you, then you can do what many of our customers do... keep your master catalog in some other program (e.g. LightRoom) and use Capture One Pro as your raw processor.