Val Gardena can be reached using the Brenner Motorway (A 22).
Coming from north, follow the route Innsbruck - Brennero - Chiusa. Coming from south, follow Verona - Trento - Bolzano. Take the Chiusa/Val Gardena exit. Following the well-marked roads, you should reach Ortisei in about 20 minutes. Follow the white indications

Google Earth coordinates:
46° 34.23 NORTH
11° 38.11 EAST