Enter db values of select's radio

I have a query. How can I enter the data of a set of select's radio into my database ?, I mean, I have a list of students that I need to take assistance from and the list is automatically generated along with the select's radio.

 $template_asistencia = '
    <form method="POST">
    <div class="item">
        <table>
            <tr>
                <th>Nro.</th>
                <th>Apellidos</th>
                <th>Nombres</th>
                <th>
                    <form method="POST">
                        <label>Fecha</label>
                        <input type="date" name="fecha_asistencia"  value="'.date("Y-m-d").'"pattern="[0-9]{4}-[0-9]{2}-[0-9]{2}">
                        <label>Curso: '.$grado.'° "'.$paralelo.'"</label>
                        <input type="hidden" name="grado" value="$grado">
                        <input type="hidden" name="paralelo" value="$paralelo">
                        <input type="hidden" name="r" value="asistencia-add">
                        <input type="hidden" name="crud" value="set">
                    </form>
                </th>
            </tr>';
    $count = 1;
    for ($n=0; $n < count($asistencia); $n++) { 

        $template_asistencia .= '
            <tr>
                <td>' . $count . '</td>
                <td>' . $asistencia[$n]['apellidos'] . '</td>
                <td>' . $asistencia[$n]['nombres'] . '</td>
                <td>
                    <form>
                        <label><input type="radio" name="tipo_asistencia" value="presente"/>Presente</label>
                        <label><input type="radio" name="tipo_asistencia" value="falta"/>Falta</label>
                        <label><input type="radio" name="tipo_asistencia" value="atraso"/>Atraso</label>
                        <label><input type="radio" name="tipo_asistencia" value="licencia"/>Licencia</label>
                    </form>
                </td>
            </tr>
        ';
        $count++; 
    } 

    $template_asistencia .= '
        </table>
        <input class="button  add" type="submit" value="Guardar lista">
        <input type="hidden" name="r" value="asistencia-add">
        <input type="hidden" name="crud" value="set">
    </div>
    </form>
    ';
    printf($template_asistencia);

And I do not know how to insert the data that I take from the radio to my db. Thank you for your attention and for your help. : D P. D .: work with mysqli.