What do I have to do when I answer an extract question for A Level History?

One crucial thing to remember, which is such a common mistake by students, is to remember it is an EXTRACT. The texts are not "sources", they are extracts from historians writing their take on the events of the past.
The question asks you to assess how "convincing" the extracts are in relation to a topic you have learnt. It is important to know exactly what this is asking you to do.
The extracts are the opinions of historians on the events of the past. Historians have taken the "facts" that you have learnt and formed a judgement on the event. The question is asking you convincing these extracts are- this very simply means- how well does their judgement match up the knowledge you have learnt? How accurate is their judgement and opinion, given what you know? How much have they mis-judged the historical truth?