In an hour-long engagement held at Windsor Guildhall, Prince William and Kate thanked a dozen of volunteers responsible for making the day itself so "extraordinary" as well as those leading to it.
WATCH: Prince William and Kate make special trip to Windsor
Speaking about the preparations, William revealed how he, Kate and the children had carefully watched it all unfold whilst doing the school run.
"When we've been doing the school run, we've been able to see the preparations going up. We've seen it growing," Kate said.
Prince George and Charlotte continued to go to school following the Queen's death but attended the State Funeral
"It must have been quite a mission. Having gone backwards and forwards last week, we could see it slowly growing. It seemed so well organised."
The Princess then added that her children, Prince George, Princess Charlotte and Prince Louis had been particularly "beady-eyed" and having spotted drones flying around the area for security reasons, couldn't help but ask their parents about them.
Last week, the couple revealed that their three children were continuing to go to school during the public mourning period to give them a sense of "continuity" and "normality".
Mum Kate made sure she supported her children during the difficult day
School teacher Elaine Gee, from Woking, told PEOPLE of her conversation with William: "Prince William spoke about George, Charlotte and Louis, saying that they were trying to keep some sense of continuity for them at school and keep things as normal as possible."
She added: "Kate and William were both very kind and gentle and genuine. It was very special – definitely a moment I will always treasure."