From the airport:
Take A3 toward S. BERNARDINO/CHUR merge into  A13. Then   exit number 22, toward THUSIS-SÜD/ST. MORITZ/TIEFENCASTEL. Turn LEFT onto TUNNEL SILS. Stay straight to go onto 417. Enter next roundabout and take 1st exit onto 3.  Enter next roundabout and take 3rd exit onto 27. Pass through 1 roundabout. Enter next roundabout and take 2nd exit onto 27/VIA GREVAS. Enter next roundabout and take 1st exit onto 27. Enter next roundabout and take 1st exit onto 29. Turn Left onto VIA MAISTRA.