Objects (object: Represents a view of a directory service class. Objects represent specific network resources and have values assigned to their properties.) are represented as object lifelines (object lifeline: In a sequence diagram, a representation of the existence of an object at a particular time. If the object is created or destroyed during the time period the diagram represents, then the lifeline stops or starts at the appropriate point.), that is, in terms of their existence at a particular time. Adjust line length to indicate an object's creation or destruction.
Arrows represent messages (message: In a sequence diagram, a communication between objects that conveys information and results in an action. A message is represented by a horizontal arrow.) between objects. An object can also send a message to itself.
Add an activation (activation: In a sequence diagram, the time period during which an object or actor is performing an action. Activation is represented by a thin rectangle.) (also called a focus of control) to a lifeline to indicate the time period during which an object is performing an action.
A return message is shown as a dashed line.