If you arrive from the airport, you can take the bus "Alfa" which leaves every hour from the airport station to Alghero Central Station. You have to buy the ticket at the airport, the ticket costs € 1. Once you arrived at the central station, just walk for 10 minutes and you will reach the apartment. Send me a message when you're on the bus, in this way, I will be in to expect the apartment to give you the keys and welcome.