Function Reference/wp link pages

This may be a stupid question but since I am still in the learning phase of WordPress, I plan to ask it anyhow.

I was reading about the wp-link pages because I needed to add pagination to a certain page of mine and they have given the following code-

Usage
<?php wp_link_pages( $args ); ?>

and they have also listed down certain parameters.

I don’t know where to write the usage code and where to place the parameters.

Kindly assist. Thanks in advance.