Edit links on classic SharePoint site

Hello!

I'm hoping someone can help me with editing a very old classic SharePoint site please!

I want to edit the URL link within the menu along the top...but clicking Edit Links doesn't let me edit the drop-down menu part (I need to edit the URL at link "B" located within "A", within "S"?  What am I missing?? All Edit Links lets me do is edit "S".  I am an Admin of the site.