What preparations did Anne and Margot make in the morning before leaving for a safe hideout?

The Franks left everything at their house as if they were just stepping out, and put on as many clothes as they could.

The Frank family was very careful before they went into hiding.  They did not want anyone to know that they had run away.  The plan was to make their house look like they were just living there and would be back any minute.

Margot is called up first, which shocks Anne.  She is only sixteen years old.  They assumed their father would be called first.  This is the Frank family’s signal to go into hiding.

In this way, the Gestapo will not realize that the Franks are in hiding until they are safely hidden away in the Annex.  The family had to leave most of their possessions behind and their house just the way it was.  They brought just what they could carry, wearing as many of their clothes as they could. 

No Jew in our situation would dare leave the house with a suitcase full of clothes. I was wearing two undershirts, three pairs of underpants, a dress, and over that a skirt, a jacket, a raincoat, two pairs of stockings, heavy shoes, a cap, a scarf and lots more. (WEDNESDAY, JULY 8, 1942) 

The family does not say good-bye to anyone, but they leave a note for a neighbor to take care of Anne’s cat.  The cat is the only one Anne says good-bye to.  Anne packs whatever she can into her school bag, making sure to take her diary.  She will not look unusual carrying a school bag. 

The stripped beds, the breakfast things on the table, the pound of meat for the cat in the kitchen -- all of these created the impression that we'd left in a hurry. But we weren't interested in impressions. We just wanted to get out of there, to get away and reach our destination in safety. Nothing else mattered. (WEDNESDAY, JULY 8, 1942) 

Anne and Margot went by bicycle, followed by their parents.  The bicycles had to be hidden when they arrived.  Anne felt that she was riding off into the great unknown because she did not know where they were going.  She just knew that her father had made arrangements for them to hide for the duration of the war.