i can see where your code is making a read but not a write, you have no code submitting an update to your database in any fashion. you have the reader portion you need the writer portion aka save or update.
you would need something like this code, not perfect though gives you the just of it.
Private Sub save_Click(sender As Object, e As EventArgs) Handles save.Click
sqlQRY = "Insert into " database" (Qty) values ('" & Qty.Text & "')" /'or your cell of the datagrid
Dim cmd As New OleDbCommand(sqlQRY, conn)