の joins two nouns: N2 is the main word, N1 is extra information about it (belonging, group, type). “N1's N2 / N2 of N1”.
ミラーさんは IMCの しゃいんです。
Mr Miller is an employee of IMC.
わたしは にほんごの せんせいです。
I am a teacher of Japanese.
N2 is the main noun — the thing the phrase actually refers to. N1 is extra information that narrows it down: whose it is, which company or group it belongs to, what kind it is. IMCの 社員 is a 社員 (an employee); IMC only says which employee.
The order is fixed, and it is the reverse of English “of”: extra information + の + main noun. Whatever stands last is what the phrase is about.