Olympus OM-10 with 50mm f/1.8 lens and original box
The OM-10 is a 1979 35mm SLR, a member of Olympus's popular OM series that began with the OM-1 in 1972. As with the other OM-series cameras, the OM-10 is a smaller and lighter option than earlier competing SLRs, such as the Pentax Spotmatic or early Nikon Fs, which are bigger and heavier. The OM-10 is meant to be used in aperture priority mode: set the aperture ring (which is at the front of the lens, note that it's not the ring at the back!) and the appropriate shutter speed from one second to 1/1000th of a second will display in the viewfinder. The camera can also be set for bulb exposures, and can be used with a manual adapter (not included), but the best way to get the most out of this camera is to lean in to the aperture-priority design. Need to control your shutter speed? Just turn the aperture ring until you get a corresponding value that works for you.
Don't forget to turn the camera off (this really means turning the meter off) when not in use to prevent draining the battery. The switch is at the top left when you look down at the top of the camera.