This a closed circuit, enter on it from the closest point based on your location and enjoy a 4 hour ride covering cities, country villages, twisty roads, mountain road and nice straights.
Note that there is a 6€ daily toll in Gerlos pass, if you like it I recommend getting the yearly ticket for 44€.
Make sure to respect the speed limits when entering urban/village areas as on average you will have 1-2 encounters.