Add Custom header to Template

I’d like to add a custom header to my site but have no idea how. Attached is a copy of the header.php file. The reason I want to do this is since my current header size is cutting off the homes and contact us buttons on my site. Making it difficult to navigate the page. Thank you in advance for your help.

Jay

[Excessive code removed – please see the forum guidelines re: posting code – you must use a pastebin for that much code]