A link has two ends -- called anchors -- and a direction. The link starts at the "source" anchor and points to the "destination" anchor, which may be any Web resource (e.g., an image, a video clip, a sound bite, a program, an HTML document, an element within an HTML document, etc.).
Think of anchors like bookmarks within a page. The correct term to use is anchors, but I find it easier to explain them using the term bookmarks instead.
Each bookmark has to be UNIQUE, so when you decide you want to be able to jump to that bookmark you need to add to that part of your html:
You can jump here later using the links elsewhere on this page
Now at the top (or bottom or wherever) you decide to put a link to your bookmark you simple put a hyperlink tag, but instead of putting an entire URL you just put #name_of_your_bookmark. And it will use the existing URL and jump to that bookmark. So for my example I would write the following which users could click on to jump to my defined bookmark:
Click HERE to jump to my bookmark
Note that the #my_unique_bookmark is EXACLTY the same where defined and where clickable.