More than 5 rounds of online exercises, 2 rounds of interviews with their HR interns that they wanted to train and used my time to do so. They were the ones that approached me at the beginning to apply, and when I opted out of the process they insisted that I continued because they liked my CV. And after all of this... they rejected me. High-difficulty brain-teaser questions and logical puzzles that had nothing to do with the role I applied for and wanted to test "the way you think". Probably, the 10th stage of the process would be to take me on a boat, leave me on the Nemo ocean point and test which direction I would choose to swim in order to save myself. Generic feedback in an email form after many rounds. Very unprofessional overall.

The initial fase is the screening of the curriculum, then you have to complete the tasks and finally there will be an interview/offer. You should study what they tell you it's necessary, if they don't tell you anything preparation may not be required