Conditional tag for link on index page

I need some help here. I am trying to put a link only on my index page. I know it’s a conditional tag I need to put in but I don’t know how and where.

Here’s the link I like to put in my index page:

<h2><?php _e(‘Marketplace’); ?></h2>

<table cellSpacing=”0″ cellPadding=”3″ width=”100%” height=”100%” border=”0″>
<tr>
<td>
What Nots
</td>
</tr>
</table>

WHAT should be the tag I use? And WHERE should I put it?