You can think of your Cambridge IGCSE German course as having four main areas of skills and understanding:
What does the AO mean?
This is the part of the course where your ability to understand recordings of spoken German is assessed.
What do you need to be able to do?
This is the part of the course where your ability to understand different kinds of written German will be assessed.
AO3: Speaking
This is the part of the course where your ability to speak German will be assessed.
This is the part of the course where your ability to write in German will be assessed.