Number + 层 + Noun
层 (céng) is a measure word used to count layers, levels, or stories of a building. It is placed between a number and a noun, as in 一层楼 (one story of a building). It can also be used figuratively, as in 一层意思 (a layer of meaning).
我家住在第十二层。
Wǒ jiā zhù zài dì shí èr céng.
My family lives on the twelfth floor.
这栋楼一共有三十层。
Zhè dòng lóu yígòng yǒu sānshí céng.
This building has thirty floors in total.
他的话里还有一层深意。
Tā de huà lǐ hái yǒu yì céng shēnyì.
There is a deeper meaning hidden in his words.