In fat 12, how many bytes does each directory-entry use to define a file or subdirectory in a directory?

If I've got it correct, in FAT12, each directory-entry use 2 bytes to define a fire or subdirectory in a directory. It's a field that called the First Logical Cluster that is needed to specify where the file or subdirectory begins. Is the value of the First Logical Cluster is "0", then it refers to the first cluster of the root directory.