I have completed Professional Scrum Master I this December and here is what my experience about the preparation for the exam:
- Read the Scrum Guide from scrum.org. It is just 16 pages document that is available in multiple languages. Note that there is minor difference between Scrum Alliance and Scrum.org in some of the numbers. So, it is advised not to mix the both for your exam.
- It is advised that working in a Scrum team gives more insight than just reading about the Scrum.
- Once you feel comfortable about the Scrum literature, go for open assessments for PSM I in scrum.org.
- If you get 100% pass marks every time you attempt the open assessment then you are halfway in the battle as you may get some of the questions from these assessments.
- Even though the document does not speak about the Burn down chart you may get a question or two from that and so familiarize yourself with that.
- Follow the forums in the scrum.org by registering yourself.
If you are new to Scrum then it is better that you take a session on that. Otherwise, the training is not mandatory. Finally, get password and appear for the exam.