I created a button as shown in the Access Developer 24 course.  I have it working to create a copy of the fields of parent and with one child table. However, I have two children tables that I need to copy the fields from to create a new record. This is my code.
   'copy the Purchase Order Details and Fundsource Details detail ()
        
    Set rsOld = CurrentDb.OpenRecordset("SELECT * FROM tbl_PurchaseOrdJunction, tbl_FundJunction WHERE ID_BlueTag=" & ID_BlueTag)  'Pull data from the junction table not the PO Table
    Set rsNew = CurrentDb.OpenRecordset("tbl_PurchaseOrdJunction, tbl_FundJunction")  'Pull data from the junction table not the PO Table
    While Not rsOld.EOF
        rsNew.AddNew
        For Each Fld In rsOld.Fields
            If Fld.Name = "ID_BlueTag" Then
                rsNew!ID_BlueTag = NewID
            ElseIf Fld.Name <> "tbl_PurchaseOrdJunction, tbl_FundJunction" Then
                rsNew(Fld.Name) = rsOld(Fld.Name)
            End If
        Next
        rsNew.Update
        rsOld.MoveNext
    Wend                'While end
    rsNew.Close
    rsOld.Close
    Set rsNew = Nothing
    Set rsOld = Nothing

I get an run-time error 3079: The specified field ID_BlueTag could refer to more than one table listed in the FROM clause of you SQL statement.