1. No, you dont have to add anything to functions.php
2. you cannot use the_secondary_content() unless that’s a function you’ve created yourself..
In order to output the value of the field you can use either:
and this should work if you put it inside your loop as long as it’s a standard loop and not just a foreach or something.
Are you certain that the “who we are” page uses page.php and not a custom template?