Heya
Don't stress so much, it's all good. With regards to your question, just make sure that you identify aspects of the source which answer the question.
When you talk about the aims and purpose of history, make sure you talk about what history seeks to achieve. Remember to discuss that there are different views on what history seeks to achieve (ie objectivist vs subjectivits views) - make sure you refer to these, explore how the source(s) elaborate and present themselves in favour of either viewpoint.
Above all, make sure you refer to the source often in your answer. A lot of marks go to correct source analysis so ensure that it is well referred to when discussing the different views on history's purpose and their subsequent implications. Try to have some other sources to write about fixed in your brain which present contrasting viewpoints of history.
All the best, I hope this answers something.
You'll do fine.
Josh
~boycee!~