I suppose the first point to make is that the focus of the first two questions is now very much on how language is used (AO1) to create meanings and represent the topic (AO3), rather than on the types of texts they are (which now comes under the remit of Question 3 and the new AO4).
AO1 and AO3 are quite distinct on the new specification, so you can pick up AO1 marks for labelling and exemplifying word classes, sentence functions and higher level grammar features such as the passive voice, progressive aspect verbs and clause types, but to get AO3 marks you need to explain what these language features do.
For example, you could get yourself a Level 5 mark (9 or 10 AO1 marks) by identifying (correctly!) something like the following range of language features: noun, verb, adjective, 2nd person pronoun, present tense verb, simple sentence, a minor sentence and a relative clause. But if you left it at that, you'd probably get something like 2-3 marks out of 15 for AO3 at best. What we need to see is some useful discussion of what each of these actually means in its context - not just catch-all generalisations such as "The 2nd person pronoun makes the text more personal." - and (crucially) how they help create a representation of whatever it is that's being discussed. Take the example from a Cancer Research UK below:
If you start with AO3 this time, you might then move on to talk about how time is represented in the rest of the extract above. Several adverbials of time are used: "for a long time", "someday soon" and "anymore". Why are these important? They seem to suggest that time is important and that a turning point is about to be reached.
There's plenty more you could look at in this short extract or in other parts of the ad (like below) but this is a start and (I hope) illustrates what's needed at this level.
So, what's the difference between meanings and representation? To my mind, it's the difference between looking at the possible effect of a single language choice (e.g. the use of different pronouns to show separate sides) and the overall effect of a number of these choices on how the topics are shown to us (cancer as an opponent in a battle; Cancer Research as an organisation fighting on our behalf).
There will be another post soon, looking at other approaches to meanings and representations.