Hi there - I came across this post thanks to a link from the 'unanswered threads' by the community team. I hope I can provide some info for you, which is purely from a personal standpoint (I work for a University which doesn't offer Education so I am not aware of the interview process etc.)
I do, however, have friends currently studying Primary Education so I know a little about the work they have been doing. You can find a wealth of resources, lesson plans etc. by doing a quick google search, but the ultimate question here is what do YOU want to choose? What age range are you most comfortable with firstly, and that will give you a bracket for the resources you should look at. Then think about what you want to teach them about - this can cover lots of topics and may be a question you are asked so worthwhile to think about. For younger children, the Elmer series is often used (because it covers topics like personality, diversity, acceptance etc.), or are you more comfortable with Geography, Science, Maths...? Pick what you want to teach them about, as you are likely going to be more confident with your reasons for choosing it if you really understand the topic. For the resources themselves, the stipulation is clear to keep it simple (pen and paper type things) so keep to that brief. Whilst there's lots of technologies out there, try to keep it simple and transportable like books or paper versions of materials rather than having fancy gadgets. Teachers have limited budgets for materials, so keep that in mind when selecting.
I hope this helps - as I said, I'm not aware of the interview process personally but this is my interpretation of the brief given. Best of luck!
Charlotte