A regular manual will follow. The following example should only show how to start.
/** @var \HeikoHardt\HhdevFpdf\Fpdf $pdf */
$pdf = new \HeikoHardt\HhdevFpdf\Fpdf();
$pdf->AddPage();
$pdf->SetFont('Arial','B',16);
$pdf->Cell(40,10,'Hello World!');
$pdf->Output();