The airport station is called Havalimanı, airport in Turkish, and they all go to the same direction. If you look on the map, that’s that red line M1A.
You will have to change at Zeytinburnu station, the fourth from the airport. Go through the barriers and take the tram (tramvay in Turkish) towards Kabataş (pronounced kabatásh). You need to get off at Cemberlitas station, we are down the hill by the Kuveyt Turk Bank. You need to take the first left, and you will see Vizyon City Hotel. You collect the keys from the reception.