Congrats on the camera. Standard 8 tends to be even more niche than Super 8, but I personally prefer it - it's the smallest format so the most grainy, but it's also more like 16mm in that it often uses interchangeable lenses, spools and a pressure plate. The flashes and light leaks that are part of daylight spool filming give it a wonderful character, and the cameras are usually well built and compact.
Standard 8 film is getting harder to find but is still available - in the US try John Schwind or Dwaynes or Spectra or B&H or LIFT. I'm assuming you're in the US since it's generally Americans who forget to mention where they are in the world.
The seized focus rings in your lenses will be due to dried up grease in the focus threads. A bit of heat applied with a hair dryer will often loosen them up but they'll probably stiffen up again when they cool. If you can get some oil into the threads (but not on the elements) it may help, but ideally the lenses need a service. Given the low value of D-mount lenses that's probably not a sensible idea though. If you pull them apart yourself you'll likely lose their collimation which will be a problem since with non-reflex cameras like your Revere you need to rely on the focus scale to get things properly in focus. It might actually be better to just get another lens, maybe a standard angle 12.5mm focal length, though close up portrait shots with a telephoto are fabulous in 8mm..
No idea where to find a manual, but 8mm cameras like this are pretty simple - wind it up and press the run switch! Loading always follows a Ω pattern, any spool 8mm camera will be the same so check any instructions you can find. You'll need a lightmeter (or iphone app) to set the lens aperture, at 16 frames per second the shutter speed will be around 1/35 second.