The place to start is the API Javadoc pages, that you can find in the downloads.
The simplest way is to use net.sourceforge.atomicdate.Date, which is an extension
to java.util.Date. For example:
// The default constructor automatically synchronizes with the default server.
final Date date=new Date();
// The date can be synchronized anytime.
// You can explicitly release the resources. If you don't, they'll be released
// when the object is garbage collected.