QOS basics

I am running the latest 5.21 Router OS on my devices. I have VOIP phones transmitting across wireless links to my edge router, an RB1200. I’ve enabled QOS on the RB1200 by some examples I’ve come across on here. My wireless links are also by Mikrotik devices and use NV2 and transparent WDS. Do I need to put the same QOS rules on those to really get my proper priorities? What if there is another router behind the wireless link behind the RB1200? Would that router also need the same QOS settings?

QoS is locally significant for that router, waht you can do is marking the traffic and do QoS on each router through the packet will pass