Cannot customize using plugin options outside of the sidebar

You suggested the following in your readme:

Insert the function <?php if( function_exists( 'taxonomy_list_widget' ) ) echo taxonomy_list_widget( $args, $id ); ?> where the list should appear, specifying $args as an array of arguments and, optionally, $id as a string uniquely identifying this list.

I added that code to functions.php. But when I tried to specify the $args, the changes didn’t show up.

Here is my site: http://explainthis.lilahrap.com/

My goal is to have “Select Tag” say “Select Topic” in the navbar, to organize them by count, and to exclude about 10 of my tags. I specified my array of arguments using the following code. Can you clarify what I’m doing wrong?

<?php
 if( function_exists( 'taxonomy_dropdown_widget' ) ) echo taxonomy_dropdown_widget( $args, $id );
        $args = array(
            'orderby' => 'count',
            'select_name' => 'Select Topic',
            'incexc_ids' => 28, 29, 30, 31, 33, 36, 38, 40, 42, 43, 44,
                    );
?>

https://wordpress.org/plugins/tag-dropdown-widget/