Register, buying a vehicle (Amman)

Interested in buying a rugged car that would enable easy after work hikes and trail runs, plus weekend camping trips, and keen to do what I've done in other countries: buy a beat-up but functioning smaller SUV or truck.

I hear that in Jordan one must buy a car under five years old in order to get it registered in the country -- but what does that mean?

Why must one do this? Does registration mean insurance?

Thanks!