У меня много вещей и мебели -I have many things at room and a lot of furnityre.
У тебя дома есть пианино?-Do you have a piano at home? Yes? I do/
У тебя много стульев?- Are there many chairs in your room?- Yes,there are five chairs
У тебя много книг?-Do you have many books? Yes, I do