install header in shopify

I am looking for someone to install a header on my Shopify store. I have a design ready to go, but I need help determining the size of the header. The ideal candidate should have experience with Shopify and be able to assist me with determining the appropriate size for the header. Additionally, the header should include a navigation menu.
attached shows to switchout cafebrew with new header and create editable link bar attached below it as it shows
the announcement bar remains