[Plugin: Thesaurus] Adding code

I’m kind of confused on the instructions here. Has anyone used this plugin? Where would you put the <?php thesaurus_print_lookupform(); ?> exactly? I would like it to be on the “new post” page so I could use it while making a post.

Researched the owners site and google and could not find anything. Anyone know where I would put this to get what I’m looking for?

Thank you