On the target page, open text editor and select a word you want to be the anchor. Click on the hyperlink manager, and the second tab across the top is "anchor" - go to that tab and write in the name you want to use for the anchor. Close and save your work.
Go to the page from which you want to link to the anchor. Go into edit mode, select a word or phrase that is going to be the link, and click again on the hyperlink control. Select the portal page from the "page" dropdownlist where you created the anchor. Then click within the page URL and hit the "End" button. At the end of the link, write "#" followed by the name of the anchor.
Save your work, and click on the word or phrase you just made into a link. It should take you to the page, as well as to the place on the page (vertically) where the anchor exists.
The hyperlink tool looks like it should be able to provide a list of existing anchors from the target page, but I don't see that happening. So I might be missing something about that part of the hyperlink manager. If so, and someone knows, please chime in!
But what I have described here should work for you. I just gave it a try and it worked for me.