Example of TSync.SynchronizeMethod

I need an example of TSync.SynchronizeMethod as I don't find one in Internet, Especially how to declare and implement the method needed as a parameter,

I need to access a data module's own comps and methods and I have the following code:

type
  TSyncGUI = class(TIdSync)
  protected
   FListBox: TListBox;
   FMsg: String;
   procedure DoSynchronize; override;
  public
   constructor Create(AListBox: TListBox; AMsg: String);
   class procedure AddMsg(AListBox: TListBox; AMsg: String);
  end;

constructor TSyncGUI.Create(AListBox: TListBox; AMsg: String);
begin
FMsg := AMsg;
FListBox := AListBox;
inherited Create;
end;

procedure TSyncGUI.DoSynchronize;
begin
FListBox.Items.Add(FMsg);  // Self.lstLog.Items.Add(FMsg) // //Self must point to the data module or form instance
if FListBox.ItemIndex = FListBox.Count - 2 then
  FListBox.ItemIndex := FListBox.Count - 1;
end;

class procedure TSyncGUI.AddMsg(AListBox: TListBox; AMsg: String);
begin
with Create(AListBox, AMsg) do
try
  Synchronize;
  finally
   Free;
  end;
end;

I can refer to the Data module with its name but it is not valid in my situacion as I create various instances of this data module at runtime and I need to refer to it with Self, inside the Sync class Self refers to the Sync class not to the data module's instance..
thnx