Answer:
He tells them to be as quiet as possible and not to wear shoes so as not to make noise.
Step-by-step explanation:
Mr. Frank and the family were Jews and were hiding in a commercial building, trying not to be captured by the Nazis and sent to concentration camps.
As stated above, they were hidden in a commercial building, where workers in a company operated during the day. In order not to be discovered, Mr. Frank suggested that everyone stay as quiet as possible during, moving as little as possible, and if it was necessary to move, do not wear shoes when walking, leaving your feet only in socks to avoid noise.