In the case of those objects that have data type equivalents the conversion from the original data type into the object equivalent will be provided automatically when you apply one of the object's methods to the data. You should never need to actually create objects of those types directly.
Static objects are intended to be used directly. The other objects are intended to be used the way you would use a class in an object oriented language - as the basis for creating your own objects.
This article written by Stephen Chapman, Felgall Pty Ltd.