changing Pilcrow

I need to add a link to older posts at the bottom of the previous posts column. I have read all of the posts I could find regarding this topic. I was able to locate the index.php file using the file manager, but it was very short and did not include the text to replace.

<div class=”pagenavi”>
<?php if( function_exists( ‘wp_pagenavi ‘ )) { wp_pagenavi(); } ?>
</div>

Thanks for your help.