How to customize a header menu in Blockshop theme?

[peter550]

Hello everyone, 

I am after recreating this header bar with the menu items on the left but in the centre of the logo, an instagram icon, cart and login button. Whenever I move the menu text not to centre it places them below the logo on the left. 

site p word is test and the site is https://laz-the-plant-scientist.myshopify.com/ theme is blockshop

Thanks!

This is what i want it to look likeThis is what it looks like now on shopify

[peter550]

 I forgot to mention, I would also like to increase the size of the menu font and add a CTA button which allows you to download a PDF (see above screenshot - 'Free botanical guide') 

Thanks!