Our first job was to go to the editorial planning meeting to find out how the BBC team decide what news stories to cover.
We created our own running order for the programme and had a debate about what topics should go on air.  We wanted to cover education in different countries, pollution and child abuse.
Then we compared our running order with the actual one for the Radio 4 show.
We only had two similarities - a story about the Queen's opinion on the EU and how much we pay for our energy bills.
While presenter Mr Mardell and the team prepared for the lunchtime show we went for some smartphone training.
It was really interesting and helpful because it taught us how to make professional videos and photos. Top tips included how to film a five-shot sequence, with each part lasting eight seconds.
With it getting closer to one o'clock, we went to listen to World at One being broadcast live in the studio. We watched from the editorial room where they were taking live calls.
It was really interesting, but we knew what was going to happen beforehand because we'd been in the planning meeting!
When Mr Mardell came off air we were able to interview him, and we joined him in the studio to ask him some questions.
We asked him what he most liked about presenting World at One and how he got his job as a journalist.
He told us his favourite part of the job is meeting lots of new people and persuading them to give their real opinions on air.  He explained that he became a journalist by following his talents and started doing journalism at university.
Then we asked him what his most awkward moment was. He said he hasn't had any but that he is always worried that he won't be handed the script by his producers on time and that he is scared he might say something wrong.
We loved the whole day at New Broadcasting House in London.
Berdan said he was inspired to be a  journalist, while Sudnaz would like to be an author.
School Reporters Berdan and Sudnaz, from Heron Hall Academy, Enfield, went behind the scenes at BBC Radio 4's The World at One and asked presenter Mark Mardell to reveal his most awkward moment.