how does annemarie use what her uncle has taught her and her observations of Kirsti's earlier behavior to deal with the German soldiers

She needs to behave in as silly a fashion as possible so that the soldiers will not suspect her of any behavior for which she could be arrested. She wants them to believe that she is nothing more than a silly child and that she is simply an inconvenience. She has to appear unafraid and not at all involved in any kind of war effort if she is actually to do her carrying of something hidden and keep the soldiers away from her.