The parking for the start of the walk to the Fyrish Monument can be found about a 20 minute drive from Dingwall. Or you could catch the train to Alness and walk (just over a mile (2kms) extra walking). For full details see - https://www.walkhighlands.co.uk/ullapool/fyrish-monument.shtml
The above link takes you the shortest route to the monument, but it is quite steep all the way. If you go up the path that is at the right of the carpark, it is a longer but steadier route with a short steep incline at the very end of the route as you near the monument. Both ways you need good waterproof footgear and remember the changing weather all year round.
The view is well worth the walk. You can see the town of Evanton directly below, as well as Invergordon and Alness.