You didn't tell us what kind of camera, or the ISO.
For a film camera using ISO 100 film, start at 1/125 second @ f16 for subjects that are directly illuminated, and f5.6 for backlighted subjects without fill flash.
one sixteenth of a second.
An F Stop refers to a ratio used in a camera lens. It is concerned with the amount of light the lens lets in, how fast the camera can take a picture, and how much of the picture will be in focus. With pixels, it is possible to overcome some of the restrictions of film cameras. First, if you have a low f stop, like 1.2, and you have a lot of light, you can take a picture real fast. Only the object you focused the camera on will be in focus. If you use a high f stop, like 22, you will need to slow down your shutter speed. Your subject will be in focus and so will the background. The old point and click cameras had about a shutter speed of 1/125 of a second, a distance of 8 feet, and an f stop of about 8. The person would be in focus. The background would not.
The "mm" marking represents the focal length of the lens as measured from the optical center of the lens to the film plane when the lens is focused at infinity. If the lens is a zoom, focal length is expressed as a range such as 28 - 80mm, which means it can be infinitely varied from one length to the other. Most zoom lenses accomplish this in part by varying the position of the optical center. The focal length or zoom range is typically indicated on the lens barrel and/or the area surrounding the front lens element. Lenses that accept accessory filters are almost never marked with a filter diameter or series size on the lens, though screw-in filters have the diameter indicated in millimeters on the filter rim. Since many lenses are stored with a filter in place, this might easily be mistaken for a part of the lens itself, particularly with screw-in filters, which normally sit flush with the front diameter of the lens barrel.