Hi supervla.
Yes PSA is the first test u have to complete before being invited to Doha for the screening interviews.
It's online and u have to answer 600 questions/statements: false/true, agree/disagree, what fit the most to ur personality. No good/bad answers like "do u enjoy having a lot of acquaintances", "u usually plan ur actions in advance", see what I mean, and it's redondant.
Seems I dont match with what they are looking for. Too bad I lost this opportunity and was not able to show my interest in interview and sim.