uses
  System.UITypes, // on elder IDE versions FMX.UITypes
  Gorilla.Viewport;

// in our form (TForm1) we added a field named "FGorilla"
procedure TForm1.FormCreate(Sender: TObject);
begin
  FGorilla := TGorillaViewport.Create(Self);
  FGorilla.Parent := Form1;
  FGorilla.Color  := TAlphaColorRec.Black;
end;