How to add IntenseDebate "comments popup link" in the template?

Hi,
I am pretty new to WordPress and am still learning as I go along.
I am currently using Worpress 3.1.3 and my site is on the Mystique 2.4.3 theme.

I am using IntenseDebate instead of the default WordPress commenting module.

For those who use IntenseDebate, you must have noticed that sometimes the Comments fail to load or take too long. I want to add a pop-up link so that when you click on it, only the comment section will open in a new tab/window.

Here is the solution provided by IntenseDebate.

Q. Why aren’t my comment links loading on my blog?
Ans. Our plugin hooks into the function comments_popup_link (http://codex.wordpress.org/Template_Tags/comments_popup_link). Please use this in your templates. That should do it.

My problem is that since I am new to WordPress, I don’t really know where to put the code and what is the exact code. I’d really appreciate if anybody can help me out on this.