Altogether there were 4 interviews total. 3 are an hour long.
1st is with an Avanade recruiter who asks you culture fit questions and it is they who decide if you're eligible to move on to the 2nd round (aka your "first" interview). The recruiter interview is anywhere from 30 mins to 40 mins.
2nd interview is with a manager within whatever role you're applying for. Come prepared to talk about your past experience and how it's relevant to the role you're applying for. Mention the times you had to use your expertise and how successful those campaigns/projects turned out to be.
3rd interview is with a senior manager. This interview might be more technical in nature and you might get situational based questions.
4th and final interview is with a director or the most senior manager. This is more of a casual interview and there might be some repetition again.
Hiring tip: Your Avanade recruiter is your champion. Feel free to reach out to them between interviews and ask questions as well. After every interview you should get feedback (either through email or a phone call) a few days after each round.