для чего нужен указатель head и на что он указывает?

unit UnitFormMain;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Buttons;
 
type
  TPointerPhoneRecord = ^TPhoneRecord;
  TPhoneRecord = record
    Name,Phone,Comment: string;
    Next:TPointerPhoneRecord;
  end;
  TFormMain = class(TForm)
    MemoComment: TMemo;
    EditPhone: TEdit;
    EditName: TEdit;
    ListBoxPhones: TListBox;
    LabelName: TLabel;
    LabelPhone: TLabel;
    LabelComment: TLabel;
    ButtonAdd: TButton;
    ButtonFind: TButton;
    EditFind: TEdit;
    procedure ButtonAddClick(Sender: TObject);
    procedure ListBoxPhonesClick(Sender: TObject);
    procedure ButtonFindClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  FormMain: TFormMain;
  Current,Head,Last:TPointerPhoneRecord;
 
implementation
 
{$R *.dfm}
 
procedure TFormMain.ButtonAddClick(Sender: TObject);
var b:boolean;
begin
 
  EditName.Text:=Trim(EditName.Text);
  EditPhone.Text:=Trim(EditPhone.Text);
 
  If (EditName.Text<>'') and (EditPhone.Text<>'') then
  begin
 
    If Head=nil then
    begin
        New(Head);
        Head^.Name:=EditName.Text;
        Head^.Phone:=EditPhone.Text;
        Head^.Comment:=MemoComment.Text;
        Head^.Next:=nil;
        ListBoxPhones.Items.Add(EditPhone.Text);
        EditName.Text:='';
        EditPhone.Text:='';
        MemoComment.Text:='';
        Last:=Head;
    end
 
    else begin
 
        Current:=Head;
            New(Last^.next);
            Last:=Last^.next;
            Last.Next:=nil;
 
            Last^.Name:=EditName.Text;
            Last^.Phone:=EditPhone.Text;
            Last^.Comment:=MemoComment.Text;
            ListBoxPhones.Items.Add(EditPhone.Text);
 
            EditName.Text:='';
            EditPhone.Text:='';
            MemoComment.Text:='';
 
    end;
  end;
end;
 
 
procedure TFormMain.ButtonFindClick(Sender: TObject);
var i:integer;b:boolean;
begin
  If Head<>nil then
  begin
      Current:=Head;
      b:=false; i:=-1;
      While (Current<>nil) do
      begin
         i:=i+1;
         If Pos(EditFind.Text,Current^.Comment)<>0 then begin b:=true;break; end;
         Current:=Current^.Next;
      end;
      If b then begin ListBoxPhones.ItemIndex:=i; ListBoxPhonesClick(Sender); end;
  end
  else ShowMessage('Добавьте хотя бы 1 запись');
end;
 
procedure TFormMain.ListBoxPhonesClick(Sender: TObject);
var i:integer;
begin
    Current:=Head;
    For i:=1 to ListBoxPhones.ItemIndex do Current:=Current^.Next;
    EditName.Text:=Current.Name;
    EditPhone.Text:=Current.Phone;
    MemoComment.Text:=Current.Comment;
end;
 
end.