How to display {{ site_name }} in menu--main.html.twig

Hello Everyone,

This is my very first time using Drupal and I'm new to twig so I'm trying to figure this stuff out. I can't seem to find an answer to my problem though.

I'm using the foundation 6 framework and it has the logo as a list item in the menu. So I hard code the list item in the menu--main.html.twig but when I try to use {{ site_name }} or {{ site_slogan }} the values are null. I'm not sure why these are null because they work in the block--system-branding-block.html.twig file.

Could someone please take a moment to educate me, I'd appreciate it.

Thank you in advanced,
Carl