There are signs pointing to Kastelli in Skala, but not to the path that leads to the castle ruins. You can follow the signs from the same named hotel on the right, climb the stairs and enter a dirt path with a panoramic view of Skala. In 5-6 minutes you will see the small church of both Agios Georgios (Saint George) and Agios Constantinos on your left (if you continue from there, you will reach Katergaki beach in 25 minutes). In order to ascend the hill of Kastelli, you have to turn back and after a 2-minute walk turn right walking parallel to a stone wall (there are no signs). Continue walking parallel to the wall and when you see a cluster of big cacti, leave this path and turn left. From that point on, things get mixed up, as the path appears and disappears. Thus, when you pass by a strange rock with a tree that seems to be growing out of it, do not hesitate to go up the slope, having the stones you see all along your way on top of the hill as a mark. In a few minutes you will find yourselves in one of the most beautiful spots of the island, where you can enjoy a gorgeous view (literally) towards all directions and explore the plateau.