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.

The Care Quality Commission (CQC) found long queues of ambulances outside the Queen Alexandra Hospital in Portsmouth, while patients with serious symptoms waited hours to be assessed.
It gave the hospital an overall rating of "inadequate".
Portsmouth Hospitals NHS Trust's chief executive resigned in May.
The Trust gave no reason for Ursula Ward's decision to stand down.
CQC inspectors, who visited in February and March, said the emergency department was "chaotic" with an "unacceptable" risk to patients.
At times, sixteen ambulances were stacking up outside the department, representing a third of the emergency ambulance fleet for Hampshire.
Inspectors found on 11 occasions, there were no ambulances available to respond to 999 calls.
Vulnerable patients including frail pensioners were left in ambulances for more than two hours.
The department was "severely overcrowded" with some patients waiting on trolleys, in corridors, or in a specialised "Jumbulance", a large ambulance, parked outside.
Waiting times were among the worst in the country with almost a third of patients waiting more than four hours to be treated.
Patients with suspected life-threatening conditions such as stroke or sepsis were not assessed quickly, and one patient with potential heart failure waited more than 5 hours for a first assessment.
The CQC said the trust had been slow to improve despite warnings and had to take "immediate action" to protect patients, including ceasing the use of the Jumbulance.
The NHS trust's Interim Chief Executive, Tim Powell, said: "We recognise the picture painted by the CQC in this report and we are very sorry that we have failed to provide to our patients, on a consistent basis, the high standards of care that we expect of ourselves.
"We fully accept the inspector's findings and... we are determined to ensure that by... next winter, our service will be better."
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.
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Health inspectors have condemned a "chaotic" hospital emergency department which they said was failing to keep patients safe.