Hi Edward,
You should be able to just Add Data Item (button at the top of the screen designer) of type String, name it whatever you want, and then make it a parameter. This becomes a screen property that you can access on your screen how you see fit (i.e.
this.MyProperty in C# or Me.MyProperty in VB). You don't necessarily need to use parameters as inputs to queries.
HTH,
-Beth
Senior Program Manager, Visual Studio Community http://www.bethmassi.com http://msdn.com/lightswitch http://dev.office.com