The hike begins at the col de Ceyssat. Park your car in the large car park. The track starts just above a few of the pass buildings.
A signpost clearly indicates the way, pretty much strait up to the top.
At first, the trail is large, fairly busy and shaded. After a few hundred meters, you'll come across the road and the scenic train tracks.
The trail continues on the other side, between gravel and rocks but remains large and sheltered by vegetation at first. Be careful, the slope is steep, and doesn't get any easier until you get to the top. There are however a few benches should you need a rest.
Gradually vegetation disappears, turns are sharper and a stunning view over the south and the Chaîne des Puys appears. The climb ends in an intense yet light atmosphere.
Taking into account the train arrival, the restaurant, paragliders taking off and the Mercure temple, there's bound to be a lot of people once you get to the top. Feel free to go around the "Chemin des Chèvres" (goats path) plateau, the view of Clermont is beautiful and the north and west slope are a lot more deserted.
Take the same path to go back down.
It'll take 40 minutes to an hour for the climb depending on your pace, about the same for the walk around the summit and properly enjoy the view, and another 30 minutes for the trip back down.