Often called Shutter Speed the shutter value is the amount of time the shutter is open.
Like the aperture, the shutter lets in more or less light.
The shutter comprises two curtains that cover the sensor. One opens and the other closes. The interval between those two actions is the shutter value. The shutters always move at the same speed, which is why the term Shutter Speed is inaccurate. But that is being pedantic!
Keep your camera in Aperture Priority and as you change the aperture, making it wider and smaller, the shutter will change too. There is a direct correlation between the two settings, but more of that another time. A small aperture lets in less light so the shutter would have to stay open for longer to let in more. A wide aperture lets in lots of light, so the shutter has to open and close quickly to let in less.
Head outside with your camera. In aperture priority change the aperture size and see how the shutter value changes with it. Make sure the ISO is not in Auto for this exercise. You should set that to its base level. This is 100 on most cameras, 200 on Micro Four Thirds. (More about ISO next time.)
Take photos of moving object at different shutter values.
Compare the shots and see how much movement appears in the photos.