From Alghero:
At the 4km of the road Alghero Porto Torres just before Sella & Mosca vineyards turn right and follow the signs.

From Porto Torres:
On the provincial road Porto Torres - Alghero, turn left just after Sella & Mosca vineyards and follow the signs.

From Sassari:
Reach Olmedo via Bonassai, just before the fountains turn right and follow the signs.

— Road from Alghero airport (Google Maps)

The coordinates for your navigation system are: 40.643823,8.351954.