Regrettably my school forced my entire year to take it. That said, this was in 2008, so the course spec may well have changed...at the time though, we had a theory exam (which was super easy but kinda boring to me, the people who were actually good at sports seemed to struggle though...) and assessed "practical" sessions - one in the school gym which was I think assessing our "personal exercise plan" we had made, and the other was assessing performance in a specific sport of our "choice" (which was supposed to be badminton for me but ended up being rounders for some reason).
For the former practical, the examiner asked us questions while we were going through our programmes - for example about equipment safety and what muscles were being exercised and so on I believe, and for the latter I believe they just observed us playing and marked us on technique or something?