Walk through code that copies data

Hello. Could someone please walk me through in detail what each part of this code is doing? Thanks

Sub copypaste()

Dim vDataArr As Variant
Dim i As Long
Dim j As Long

vDataArr = Range("B3", Range("E" & Rows.Count).End(xlUp))

For i = 1 To UBound(vDataArr, 2)
  For j = UBound(vDataArr, 1) To 1 Step -1
    If vDataArr(j, i) > 0 Then
      Exit For
    Else
      vDataArr(j, i) = ""
    End If
  Next j
Next i
    
Range("K3:N" & UBound(vDataArr, 1)).Value = vDataArr

End Sub