Move Social Icons in Main Nav to the right of menu, under site title. 7.1

Hello!

I am trying to move the social links (in this case just one instagram icon) to the right of the main menu under the site title. 

(As pictured where the arrow points). 

I have tried all the code I have found in the forum and am having no luck. 

I'm in 7.1, using the last header layout option, and we're on a business plan so code injection OK. 

I pitched a design with the menu and social on the right hand side (per the second image), and the client wanted to move it under, which looks great, but I can't figure it out and i'm losing my mind. 

Help please!

Hello!

Just coming back to say i got there in the end with some help from 

https://bamn.digital/blog-squarespace-web-design-css/add-custom-icons-to-squarespace-navigation

and 

https://bamn.digital/blog-squarespace-web-design-css/adding-font-awesome-to-your-squarespace-website

thanks to @JamesBros