The term I know for brothers and sisters is 兄弟姐妹. For example 你有兄弟姐妹吗？Do you have brothers and sisters?

brothers and sisters = 兄弟姐妹 xiōng-dì-jiě-mèi

Than you big is哥哥，姐姐, 表哥，表姐，堂哥，堂姐，younger is弟弟，妹妹，表弟，表妹，堂弟，堂妹

In modern Chinese, we use the phrase "兄弟姐妹". The meaning is "兄= elder brother, 弟=younger brother, 姐=elder sister, 妹=younger sister. Please note "兄弟姐妹" is a phrase, you cannot change the character order, they are fixed.

In general,Chinese say 哥哥，弟弟，姐姐，妹妹。