it depends on what exam board you do, I do edexel it's relatively easy. 30% is your performing ( solo and as a group) 30% is your composing ( a free composition and a set composition). this you do in your class with your teacher and is essentially coursework. the other 40% is from your exam which has 4 components ( instrumental music, vocal music, stage and screen and fusions). you should be at about grade 4 in your instrument to be confident in your coursework though.