Usually the recruitment process takes about 3 days.

1st day -open day, information about the airline, qatar and at the end they receive your Resumes.
If they are interested in you they will call you for a 2nd day (Assesment day)
3th day is usually the final interview

However if there is a large number of applicants they could split the ones who made it to the final interview, and some might have to go on a 4th day.