This is somewhat belated, but here's my school wiki; you may find it useful in terms of theory!
http://www.esfmedia.com/page/GCSE+MediaI'm sorry about confusing you, it is rather odd...
Either way, I wouldn't worry! Media is underpinned by two or three base concepts, and the rest of the theories are built up around it.
These are, unfortunately... the ones you're having trouble with.
To put it simply,
Text: the actual thing, or product viewed by people- i.e: Slumdog Millionare, The Daily Telegraph, Nicki Minaj's "Stupid Hoe"
Audience: The people themselves that view the text- they can be divided into various social classes
Industry: The media industry provides, and creates text in order to satisfy the audience, and obtain money from them.
It's not too difficult to link audience and text together, but the high points come from linking the INDUSTRY, and the TEXT to each other, and HOW the industry therefore affects the text.
For example, if a text say, Telephone by Lady Gaga was made by an indie music company, rather than one of the 'Big Four', this would affect the amount of people that Gaga reaches that is, her audience. This would mean that her star persona would be perceived quite differently in context.
As for the exam, try your best! But it's okay if you mess up a little- I dropped a 10 mark question and still managed to come out with an A*; it's very important to have good coursework!