I'm struggling with my CELTA application on functions, can anyone help?

Look at the exchange below and the labels on the right

A. Would you like to come to the cinema tonight? INVITING

We call these labels (e.g. 'Inviting' etc.) FUNCTIONS. It is another way of categorising language, this time thinking more about what the language is actually doing. Look at the dialogue below and label the function of each utterance. Put your answers in the boxes on the right. *

A: Hey Bob. *

Attracting attention

B: Yeah? *

A: Help me with this case, could you?.... *

B: Sorry, but Jenny's waiting for me *

A: O.K. Never mind. *

This is clearly an informal conversation, between two friends. Imagine a similar dialogue with the same number of lines and using the same functions between two people who do not know each other.
I'm going to be cruel to be kind here.....

I think you're giving up a little too easily - a couple of the other functions in that dialogue are quite obvious (line 3 & 4). Why not have a go and ask people if they think you're right? If you're going to do a CELTA you will really need to get your brain working Emotion: nodding
For line 3 I have requesting a favour and for line 4 rejecting a favour, is this correct?
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Yes - or even just 'making a request' & 'refusing a request'. Emotion: smile
Would 1 be responding to a question and 5 accepting a response?
What is B really doing in line 2? 'Hey Bob' isn't really a question. Think of it this way - if B didn't respond at all, what would A probably think?

Yes, I think 'accepting a refusal' is a good description.
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What function does the second line have? Yeah?