Complex sentence: In contrast to practice in other nations, the Ministry of National Defense does not exercise authority over the People's Liberation Army (which is instead subordinate to the Central Military Commission), and its role is primarily that of a liaison office with foreign militaries.
Split into simpler sentences: In contrast to practice in other nations, the Ministry of National Defense does not exercise authority over the People's Liberation Army (PLA), which is instead subordinate to the Central Military Commission. Instead, its role is primarily that of a liaison office with foreign militaries.