I take out additional fields in different places of a template the next way. I insert in item.php

$extrafields = array();
foreach($this->item->extra_fields as $item)
{
$extrafields[$item->id] = $item->value;
}

and

<?php echo $extrafields[2];?>

It works. I have two questions.
1. How to draw a conclusion of additional fields thus via the module K2 Content?
2. How to deduce Additional fields in the field "Similar materials"?
Excuse, I from Russia and badly know English therefore translated the translator.