Drive to the northernmost village Sandvik and take the mountain road. There is a gate, you can open it yourself, you just have to remember to close it again once you go through. Drive until you reach the end of the road.

Drive to the northernmost village Sandvik and take the mountain road. There is a gate, you can open it yourself, you just have to remember to close it again once you go through. Drive until you reach the end of the road. You need to drive very slow as this is an offroad and there are many stones on the road. You can hike up the mountain and reach the famous wooden bridge. 

Please DO NOT go on it if you are afraid of heights or if it is too windy.  You can go further up or down. The view is just amazing with tall cliffs and the sea stack Ásmundarstakkur in the background.  You can spend hours walking around there because it is just so beautiful. So just remember to not lose the ferry back to Tórshavn. :)