From Pürzlbach or Waltlmühlsäge you hike in approx. 1.5 hours to the Kallbrunnalm. Continue straight on to the "Käsealm". At this hut, you have the option of turning right towards the Dießbach reservoir or left towards Seehornsee and Seehorn summit.
After a good 500 meters, the forest road branches off into a hiking trail. You then walk for approx. 1 hour through a beautiful pine forest until you reach the Seehornsee lake. It's worth taking a short break here and enjoying the view (make sure you pack your swimming gear!)
If you want, you can continue your journey to the Seehorn, offering wonderful views over the valley.