1. Делаете резервную копию всех файлов сайта и базы данных;
2. Добавляете через админку 28 полей (чтобы не путаться назовите их field_pole_1, field_pole_2, … field_pole_27, field_pole_28);
3. Заголовок поля пишите какой вам удобно. Если заголовок не нужен в выводе — удалите куски кода <?php echo $fields['field_pole_
НОМЕР_ПОЛЯ']['label']; ?> в коде ниже;
4. В файле form.php в блок «Here are several standard free fields» добавляете в нужном вам месте код:
<table width="60%" border="1">
<tr>
<td rowspan="4">
<?php echo $fields['field_pole_1']['label']; ?><?php echo $fields['field_pole_1']['field']; ?><br />
<?php echo $fields['field_pole_2']['label']; ?><?php echo $fields['field_pole_2']['field']; ?>
</td>
<td rowspan="2">
<?php echo $fields['field_pole_3']['label']; ?><?php echo $fields['field_pole_3']['field']; ?><br />
<?php echo $fields['field_pole_4']['label']; ?><?php echo $fields['field_pole_4']['field']; ?>
</td>
<td>
<?php echo $fields['field_pole_5']['label']; ?><?php echo $fields['field_pole_5']['field']; ?><br />
<?php echo $fields['field_pole_6']['label']; ?><?php echo $fields['field_pole_6']['field']; ?>
</td>
</tr>
<tr>
<td>
<?php echo $fields['field_pole_7']['label']; ?><?php echo $fields['field_pole_7']['field']; ?><br />
<?php echo $fields['field_pole_8']['label']; ?><?php echo $fields['field_pole_8']['field']; ?>
</td>
</tr>
<tr>
<td rowspan="2">
<?php echo $fields['field_pole_9']['label']; ?><?php echo $fields['field_pole_9']['field']; ?><br />
<?php echo $fields['field_pole_10']['label']; ?><?php echo $fields['field_pole_10']['field']; ?>
</td>
<td>
<?php echo $fields['field_pole_11']['label']; ?><?php echo $fields['field_pole_11']['field']; ?><br />
<?php echo $fields['field_pole_12']['label']; ?><?php echo $fields['field_pole_12']['field']; ?>
</td>
</tr>
<tr>
<td>
<?php echo $fields['field_pole_13']['label']; ?><?php echo $fields['field_pole_13']['field']; ?><br />
<?php echo $fields['field_pole_14']['label']; ?><?php echo $fields['field_pole_14']['field']; ?>
</td>
</tr>
<tr>
<td rowspan="4">
<?php echo $fields['field_pole_15']['label']; ?><?php echo $fields['field_pole_15']['field']; ?><br />
<?php echo $fields['field_pole_16']['label']; ?><?php echo $fields['field_pole_16']['field']; ?>
</td>
<td rowspan="2">
<?php echo $fields['field_pole_17']['label']; ?><?php echo $fields['field_pole_17']['field']; ?><br />
<?php echo $fields['field_pole_18']['label']; ?><?php echo $fields['field_pole_18']['field']; ?>
</td>
<td>
<?php echo $fields['field_pole_19']['label']; ?><?php echo $fields['field_pole_19']['field']; ?><br />
<?php echo $fields['field_pole_20']['label']; ?><?php echo $fields['field_pole_20']['field']; ?>
</td>
</tr>
<tr>
<td>
<?php echo $fields['field_pole_21']['label']; ?><?php echo $fields['field_pole_21']['field']; ?><br />
<?php echo $fields['field_pole_22']['label']; ?><?php echo $fields['field_pole_22']['field']; ?>
</td>
</tr>
<tr>
<td rowspan="2">
<?php echo $fields['field_pole_23']['label']; ?><?php echo $fields['field_pole_23']['field']; ?><br />
<?php echo $fields['field_pole_24']['label']; ?><?php echo $fields['field_pole_24']['field']; ?>
</td>
<td>
<?php echo $fields['field_pole_25']['label']; ?><?php echo $fields['field_pole_25']['field']; ?><br />
<?php echo $fields['field_pole_26']['label']; ?><?php echo $fields['field_pole_26']['field']; ?>
</td>
</tr>
<tr>
<td>
<?php echo $fields['field_pole_27']['label']; ?><?php echo $fields['field_pole_27']['field']; ?><br />
<?php echo $fields['field_pole_28']['label']; ?><?php echo $fields['field_pole_28']['field']; ?>
</td>
</tr>
</table>
Должно получиться типа

, где значения в кавычках элемент формы <input>, если не было установлено другое значение в админке.
Это всё «на глаз» — проверить не где было.