Look at the file called "header.php" (using your editor).
Copy that whole file (copy) and paste into notepad.
Save that as "header_orig.php" on your PC. This will be a safe copy you keep because you'll be modifying it and you always want to keep an original copy.
Now, you can modify "header.php".
Look for a part that looks sort of like this:
It will look different in "header.php" because it will have some codex. I am only able to see the final HTML, not your PHP script.
<div class='menu-topmenu-container'><ul class="menus">
<li class="page_item page-item-144"><a href="http://throughtheivy.com/about-me/">About</a></li>
<li class="page_item page-item-159"><a href="http://throughtheivy.com/contact/">Contact</a></li>
Remove that section and then save it back.
Refresh your website and see if it is gone.
If something bad happens, you can restore it back from your saved copy.
A main point here is to always make a safe copy of any script or file that you modify.
If you were to use FileZilla (FTP) instead of the WP admin editor, you could save ALL of your theme files as a backup.