These kinds of pages use a html feature know as "anchors." These allow you to name a location in an article.
The ability to insert "anchors" in an article is not enabled by default if you are using the default Joomla editor Tiny MCE. To turn on this (and many other editor features), go to Extensions -> Plug-in Manager -> Editor - Tiny MCE -> Functionality -> Extended.
If you are using JCE for your editor, it is enabled by default.
So, edit your article. Find the place where you want to place an "anchor" and put your cursor at the beginning of the line.
Next, click the "anchor" icon on your editor toolbar.
If you are using TinyMCE, it look like this:
If you are using JCE, it looks like this.
Give it a name that makes sense and that you will remember (no spaces).
Then, for the menu, you use the type "external url" and you put #location-name as the link.
So, for example, let's say you have a location in the article that you have named "author"
You would put #author as the url link in the menu manager.
Let us know how that goes.
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