Header graphic on top, menu underneath…

How do I run the header logo all the way across the top of the page, with the naviation menu underneath?

Here’s the current website in question: https://www.myramossmanesq.com/

Here is my mockup in photoshop of how I would like it to look:
https://www.bvhprods.com/myramossmanesq.com_new_header.jpg

Thanks in advance for your replies!!!