Hi,

ATMA Exam is held thrice a year only and even though you can appear for all the attempts, only the last one will be considered for the selection. After the exam and when the result will be declared, a list of qualified candidates is released, after which the selected candidate will have to appear for the Group Discussion (GD) or Written Ability Test (WAT) and Personal Interview (PI) rounds. The final merit list will be prepared based on the ATMA scores, performance in GD/WAT-PI rounds and overall academic profile of the candidates.

Here is a link that you can refer for more details: https://bschool.careers360.com/exams/atma

I hope this helped you.