Be aware that sticky positioning may not work in some browsers (try Firefox if you have any trouble). It is mentioned here because it should be widely accepted in the near future as it is agreed as being useful and is part of the CSS specification.
Open linksinternal.html and save it as sticky.html. Try it in a browser and note the internal links (the three crammed into one line). Scroll part way down the page and the links vanish. You could pin them to the same position with fixed positioning but sticky is much more clever than that.
Place this style attribute in the opening p tag for the single paragraph containing the three links:
Note that in the browser nothing changes at first. Now scroll and everything starts as before but as soon as the link paragraph reaches the position you set (0 pixels from the top) it sticks there. If you did this with fixed positioning the list would just be stuck in that place right from the start. Using sticky you can have stuff above the links when the page is loaded - stuff you want people to see first. However once they are finished with that stuff it scrolls up out of the way leaving just the links at the top.