How to draw UML Sequence Diagrams in Visio 2013

Below are the steps to draw UML sequence diagram in Viso.

Open the Visio and
-> select the Blank Drawing
-> select the US Units
-> Click on Create
-> Click on More Shapes option in the left pane. It will open the tab to browse the shape categories
-> Go to Software and Database ->Software -> Click on UML Sequence.
     It will open up the stencils for the UML sequence diagram.

Let's say for example if we want to draw the sequence digaram for the interactions between two systems.  Ex: System 1 and System 2.

-> Drag Object Lifeline stencil to the drawing page. Double click on the box and name it System1.
-> Similarly drag another object lifeline stencil to the page and name it System2.
-> Drag the Activation stencis to the System 1 (the vertical line). Drag another to System 2 lifeline.
-> For representing any contact from System 1 to System2 like messages, API calls etc ,drag -> (Arrow) message stencil between two systems. The origin of the arrow should be on System1, Activation line and the Arrow should point to the System 2 Activation lifeline.
-> For the return message, use  <-- (return Arrow with dotted lines) stencil.
-> for any functionality within the system, use Self Message stencil.