On this page of Assassin's Creed Valhalla's trophy guide, you will learn how to unlock theSkadi's Hobby trophy. This achievement is awarded for performing a 150-metre long slide on snow.
You can earn this trophy in the first hours of the game, because the opportunity to unlock it appears in the "starting" region of Rygjafylke in Norway. Specifically, move to the Fannaraki Summit vantage point marked in the image.
The slide is made a few dozen meters to the southeast from the top of the mountain - this area is marked on the picture.
The place where the slide starts is shown in the picture above. Save the game before you start the slide. This will allow you to easily repeat the attempt in case you fail.
You have to ride down slalom-like and avoid a small hill because in these places Eivor can clearly slow down and interrupt the slide prematurely.
If you have done everything as planned, the trophy will be unlocked just after the end of the slide.