Private Sub Worksheet_SelectionChange(ByVal Target As Range)

Worksheets("Sent to Assembly").Range("a3:c100").EntireRow.Copy
Destination:=Worksheets("Parts Sent to Assembly").Range("a3:c100")

End Sub

Can anyone help changing this code to what I need, please!
I'm trying to somehow keep the contents of the "Parts Sent to Assembly"
after the "Sent to Assembly" contents have been deleted. After the contents
are deleted from the "Sent to Assembly" and New data is entered only the New
data is copied to the "Parts Sent to Assembly. Is there a way to keep the
contents of the "Parts Sent to Assembly" and the new data from the "Sent to
Assembly" be added to the next blank row. I need to keep track of all the
"Parts Sent to Assembly" but I do not need to keep track of the "Sent to
Assembly" once it is deleted. Thanks so much in advance!!!