VBA code for excel if formula

In which place you are using this code?? I mean you should use it inside a macro or another procedure like this:

Sub GetValue()

Dim myVal As Variant

myVal = IIf(Sheets("Na Cal").Range("B4").Value >= 1, Sheets("Na Cal").Range("B4").Value, "")
'Now use this value somewhere, I'm putting it in A1
Range("A1").Value = myVal

End Sub