Saving multiple checkboxes output as Array
I have modified the Custom forms in the step-functions.php to give me a Checkbox option and, for now, have this code
<?php $options = explode(',', $result->field_values);
foreach ($options as $option)
<input type="<?php echo $result->field_type; ?>" name="<?php echo $result->field_name; ?>" value="<?php if($result->field_req) echo 'required'?><?php echo $option; ?>" multiple="yes"><?php echo $option; ?><br>
When the form is posted in a new ad I want the checked values saved in an ARRAY that winds up in the wp_postmeta table in the meta_value field as a comma separated array such as "Jacuzzi, sauna, heated pool..."
Then I will pull out the values into a list. I have already made the function that does this--pull a comma-separated array into a list and just from custom checkbox values. I see that it must be jsquery that highlights the chosen checkbox arrays when the ad is first reviewed.
I have tried multiple methods to make the array happen...that after an ad is Submitted the multiple values that are normally appended in such a checkbox in html would be passed along in the browser url.
Supposedly, the  added to the name value inside the input code will "cause" php to make its own array when the name for each input field is the same, as in name="custom_checkbox_1"... I also added multiple="yes" to signify that that multiple values are expected and allowed.
This does not work when the values are being grabbed with php functions, however.
And I have tried methods in the step2.php and in step-functions.php, everything from serialize to implode, to pre-counting array methods.
My experiments have given me too many php errors or empty arrays.
Any suggestions on the slickest method?
Thanks for your kind help!