Issues with header.php

Hi have an issue with my header.php.

It has broken links to the pages. Am new to code and have worked out the bit in the code which has been edited but I dont have the original to change it back. I nee the piece of code that properly links in the about us page and conatct page that comes standard with the template.
Currently it shows in the code as linking with the page id, which isn’t working. Could someone give me the code I need to get the pages working again?

Much appreciated!
Crystal.