Delphi 2.0 - incorporateing units

Hello,

I have stumbled across Delphi programmers Corner achieve on the net. They offer of freeware (units/components) - some of which I have copied.

Q1. My problem is how do I incorporate their prewritten units successfully.
Q2. I have a particular example I would like solved.

(I realise I place the unit's name in the 'implementation uses' area of the unit calling it, but where do I go from there?)

The name of the unit is Aligrid (it aligns text in a TStringGrid) See following for Aligrid code:

************************************************************
unit Aligrid;

{Usage: There is one additional property
 "Alignment", the possible values are:
 alRight, alLeft, alCenter.
 This alignment hold for the complete grid;
 I'm currently working on one with an alignment
 for each cell.}

interface

uses
  SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
  Forms, Dialogs, Grids;

type TMyAlign = ( alRight, alLeft, alCenter);

type
  TStringAlignGrid = class(TStringGrid)
  private
    FAlign : TMyAlign;
    function GetAlign:TMyAlign;
    procedure SetAlign(const Value: TMyAlign);
    procedure Initialize;
  protected
    procedure DrawCell(ACol, ARow: Longint; ARect: TRect;
      AState: TGridDrawState); override;
  public
    constructor Create(AOwner: TComponent); override;
  published
    property Alignment: TMyAlign read GetAlign write SetAlign default alLeft;
  end;

procedure Register;

implementation

constructor TStringAlignGrid.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Initialize;
end;

procedure TStringAlignGrid.Initialize;
begin
   FAlign := alLeft;
end;

function TStringAlignGrid.GetAlign: TMyAlign;
begin
   Result := FAlign;
end;

procedure TStringAlignGrid.SetAlign(const Value: TMyAlign);
begin
   FAlign := Value;
   Invalidate;
end;


procedure TStringAlignGrid.DrawCell(ACol, ARow: Longint; ARect: TRect;
  AState: TGridDrawState);

  procedure DrawCellText;
  var
    Text: array[0..255] of Char;
    l : Integer;
    Temp : TRect;
    Alignment : TMyAlign;
  begin
    StrPCopy(Text, Cells[ACol, ARow]);
    l:=Canvas.TextWidth(Cells[ACol, ARow]);
    Temp := ARect;
    Alignment := FAlign;
    if Alignment in [alCenter] then
       if l < (Temp.Right-Temp.Left) then begin
          l := ((Temp.Right-Temp.Left) - l ) div 2;
          Temp.Left := Temp.Left + l - 1;
          Temp.Right := Temp.Right - l + 1 ;
       end;
    if Alignment in [alRight] then begin
       Temp.Left := Temp.Right -l - 4 ;
       if temp.left < ARect.Left then
          temp.left := ARect.Left;
    end;
    ExtTextOut(Canvas.Handle, Temp.Left+2, Temp.Top + 2,  ETO_CLIPPED or
      ETO_OPAQUE, @Temp, Text, StrLen(Text), nil);
  end;

begin
  if DefaultDrawing then DrawCellText;
  {inherited DrawCell(ACol, ARow, ARect, AState);}
end;

procedure Register;
begin
  RegisterComponents('Beispiele', [TStringAlignGrid]);
end;

end.    
***********************************************************