Embeding custom fields into loop

Hi

I am a newb with custom fields and am just getting used to custom press.

I am at the stage where I would like to embed my custom fields. So I can see the php – <?php echo do_shortcode(‘[custom_fields_block]‘:wink:; ?>

I know I need to put that in the page template within the loop.

Please help me out here – I want to embed it in the single post i.e. – this page – http://www.students4work.co.uk/vacancies/test-vacancy/

What file and line of the code do I insert the PHP?

Thanks for the support

Mark