Determine the radius of the circle the object is traveling around. For example, a person might be hanging off the side of a merry-go-round with a 10-foot radius.
Determine the mass of the object. In our example, the person's mass might be 100 kilograms.
Determine the linear velocity of the object. If the object makes a complete revolution once per minute, for example, then it's going 10^2 x pi or about 314 feet per minute.
Multiply the radius by the mass by the linear velocity to find the angular momentum. 10 feet x 100kg x 314 feet per minute is 314,000 kilogram feet squared per minute.