Creating a ‘template’ page..

I have installed a plugin, to activate it i need to add the following code to a ‘template page’

<?php csn_show_form() ?>

the code shows a form, i just want a blank page with this form enabled.

but i believe i can’t add PHP code to a page, i’ve tried the PHP-Exec plugin and the form showed, but when i clicked to submit the information it didn’t work.