From Griante follow the signs and the path that takes you to the Church of San Martino. When you are approximately half way up you will see a path that veers to the left. It will traverse the mountain in a southerly direction until it eventually heads up. Continue until you reach the final ascent, a long and steep field that has a few small buildings at the top of it. From there continue up and to the north to get to Sasso San Martino. (If you take the path that traverses and rises the mountain in a southerly direction you will be taken to Nava isntead). You will do a small descent before heading back up. You will come accross some old military trenches and you will eventually see over the mountain and down to Menaggio and the northern section of Lake Como. Return the same way. Avoid going down the back side from Pilone as it will bring you to Menaggio eventually, a long way from your starting point.
There is a small spring on the way up that provides some water for cooling down, but to be safe bring plenty of drinking water and some snacks. You may see goats.