[Theme Simplicity] Add more to Header

I do not have a lot of experience editing CSS code, but here is what i would like to do:

Right now the header on my website is hosted through WordPress using the simplicity theme – https://www.pmetro.org

What I would like to do is move the menu down to the bottom of the header and then place some social media icons at the top right (I would love for the site to look exactly like this site: https://psmchurch.com/)

Any advice or how to would be most appreciated!