Composing- you have to compose two pieces. One you can choose what it is, the other you will be set four briefs to choose from in year 11 and you have to write a piece based on that e.g. "Write a fanfare for the Queen's birthday". You have to submit a recording and a score (written music). The score can be on Sibelius or on GarageBand.
Listening is made up of simple questions e.g. What instruments can you hear and also extended questions which require more thought. You will need to analyse music and say the mood- much like English literature.
There is also a short dictation exercise. They will play a melody or rhythm and you have to write it down.
Hope this helps. Contact me if you have any questions.