Hello and welcome!
Coming from Malaga airport you must stop at Torremolinos centro, which is the stop just after "La Colina". From there take the San Miguel street and walk down the street, heading to the beach...
As far as I remember the train stops are in this order:
- Plaza Mayor - Los Alamos - La Colina - Torremolinos centre
- Montemar - El Pinillo
San Miguel street is the most popular street in Torremolinos, and it is next to the train station, so you will have to ask first for that street and later for "Bajondillo"...looks like in the map that Aguamarina apartments are not far from there.
Take a look at the map I made with the path to follow:
You can check also our page about commuter trains in Malaga
Let me know if it is clear