Copy/paste worksheet function

Option Explicit

Private Sub Worksheet_Change(ByVal Target As Range)

If Target.Column = 3 Then Range(Cells(Target.Row - 1, 5), Cells(Target.Row - 1, 27)).Copy Cells(Target.Row, 5)

End Sub

Thanks to someone on here (and I forgot who! But I am forever grateful to that person) I got the above worksheet code - but I now wish to alter it to suit a similar new requirement that I have - however rather than get one of you Gurus just to write the expression that I need - what I would like is for someone to give me a detailed explanation of the above code - so that I can try to understand where all the figures come from and I then want to "try" to write the new code!! If, and only IF, I fail to achieve my new requirement - I will come back and ask for help - but at first let me try.

In order for me to try, I need to be able to understand as to how the above code was constructed - so can a Guru please provide me with a detailed explanation.

Thanks;