How do i code a VBA to ask the user to select which file to use

The current VBA i have is as follows;

Workbooks.Open Filename:= _
        "\\Via.novonet\dfs\LIFE\F\test\test\test\Source Files\test\test\test 300412.xls"
    Range("A1:DK47073").Select
    Selection.Copy
    Windows("test.xlsm").Activate
    Sheets("test Data").Select
    Range("A1").Select
    ActiveSheet.Paste
    Sheets("test pivot").Select
    Range("D15").Select
    Application.CutCopyMode = False
    ActiveSheet.PivotTables("PivotTable3").PivotCache.Refresh

I want to be able to code it so the macro asks the user which file to use but will use the same steps following this?

Any ideas