They didn't have much. There was no television back then (believe it or not), but they did have a radio that they listened to very carefully and very quietly. Mr. Frank and his friends prepared the annex months ahead of when they went into hiding, so they did have some furniture, such as a table and chairs, beds, and a few personal belongings. To avoid suspicion, they put on as much clothing as they could before moving into the annex, so they probably didn't have big wardrobes. Peter Van Daan brought his cat, which caused tension between him and his father when food supplies started to get low.
I know that Anne took some books so she would be able to study while in the secret annex. She didn't want to forget about her education.
They didnt bring alot they brung clothes which they had to wear on them so no one would be suspicious and some other personal belongings covers radio beds charis and peter brought his cat which was not really a smart idea