menu on mobile and tablet view

Hello, my site is currently running on Themify Ultra Child theme. I have noticed that the menu icon for both the mobile and tablet view are currently not working (there is no icon).

I received the following response back from Themify:

"Can you please check to see if you have header.php file in your child theme? The markup for the mobile menu is not valid, so it could be you have an older version of the file in your child theme. If you don't have header.php, please reinstall the parent theme to ensure all of its' filed are in place and up to date.

Also, your child theme stylesheet is loading in the wrong order, this can cause display issues. Please follow this tutorial to make your child theme: https//themify.me/docs/child-theme.

You don't need the @import "../themify-ultra/style.css rule in your style.css either, the theme loads that automatically in the proper place. "

Can you please assist me with any (or all) of these instructions, I'm not confident making these changes myself.

If you are unable to help can you please recommend a trusted WP Developer who can assist me?

Many thanks.

Kristen