Set Wb = ThisWorkbook

This could be a start...

http://www.cpearson.com/excel/DeclaringVariables.aspx

Basically, you are declaring Wb as a variable and it is equal to this workbook, so yes, your definition would appear correct.

It would we the same as for instance, declaing a specific worksheet...

Sub dosomething()
    Dim ws As Worksheet
    Set ws = Sheets("Sheet1")
    ws.Range("A1").Font.Bold = True
End Sub

This code would only affect Range A1 on Sheet1

You're very welcome