Wolfgang Amadeus Mozart: Which few did you have in mind, Majesty?
It introduces some basic UML® concepts essential to understanding SysML®, and some essential notations and terminology. It does not expand here on use of Behaviors such as Activities and StateMachines, they are handled in more detail in other tutorial trails. It also does not cover Component, Node, Deployment, or other related metaclasses that are not UML4SysML.
If you are already a "UML ninja" by all means skip to the SysML starting point: