You can find a fully described article from http://www.silverlightclub.com/resources/1858-silverlight-lets-start-building-applications.aspx.aspx
In the following step(s) I am giving the ideas all about:
1.Create a project:Here you just start your visual studio, Select your programming language [C#/VB], Choose Silverligh Template give the name and save it
2. Adding SIlverlight COntrols:One thing is happened here, controls cannot dragged onto the designer, you can draw/drag the controls on XAML page.
(a) Naming to control:In this step just give the name to your silverligt control like for Button you can give name as : btnmySilverligtButton
(b)Adding event handlers to Silverlight controls:Here you can give the event handlers like for click etc.
(c)Testing Silverlight applications in Visual Studio:Now just press F5 and test your application