Search function mixed with json and php (sql)

Search function mixed with json and php (sql)

I write a search system, this system has 4 pages/steps, on the first 3
pages are only checkboxes to find, my problem is, i create this checkboxes
per json, and i can read only names. To convert this data for checkboxes i
use:
<?php
$jsonData = json_decode($string5, true);
foreach ($jsonData as $item) :
?>
<label><input type="checkbox" name="<?php echo $item['name'] ?>" value=""
/><?php echo $item['name'] ?></label><br />
<?php
endforeach;
?>
My questions are: How can i get values from checkboxes on the page/step 4
dynamicly? How can i from this json data create a sql query for search
results?