Overall changing out a ceiling fan isn’t difficult in concept. The most challenging part when dealing with high ceilings and stairwells is overhead work on ladders. generally speaking I found it similar to wiring any light on a three way switch, just heavier with a few nuances. I would only recommend doing this if you are physically able, and have the requisite knowledge of residential electrical systems to conduct the work in accordance with the manufacturer’s instructions and associated electrical codes where you live; otherwise call a licensed electrician. This job is slightly more time consuming than wiring a standard light and will likely take between one and two hours. Updating the fan from the 1980s was very impactful to the look of the stairwell.