What precautions must the Franks and van Daans take to remain undiscovered in the annex?

The Diary of Anne Frank, as the title tells us, is the true-life diary of Anne Frank, who spent years in hiding with her family in an attempt to stay alive and not be taken away by the Nazis. Anne tells us every single detail of her life, big or small, and we learn a lot about her.
One of the things we learn very well is how important it is for Anne, her family, and the van Daan family to take precautions so that they are not discovered. The most paramount of these precautions is to stay quiet during the day, so as not to alert the people working downstairs to their presence. The family spoke very little during daylight hours, and moved around very little, so as not to make the floorboards creak. They never flushed the toilet until the end of the day either, so no one would become suspicious or suspect that someone was living or working upstairs.
They also made sure to keep the curtains drawn during the day, so that no one out on the street could see inside. All of the windows were kept closed, with the one exception being a window in the attic. Occasionally they would open the windows a bit at night to let fresh air in, but other than this, the annex was kept sealed and covered.
To outsiders, it may have appeared that there was not even a room there at all—or, at the very least, that if there was a room, it was unused. When people came by to bring the families food, they made sure to do so at night, under the cover of darkness, so no attention would be brought to it.
https://www.annefrank.org/en/