QoS Setup for WRVS4400N

[arcpoint-la]

I am running 3CX software V8. We get intermittent problems with hearing customers and I think if I set up the QoS in my router WRVS4400N it may cure the problem. I have searched the forums for help on how to set it up but without joy.

Could you please tell me the settings I need to setup

Thank you
Bob Duncan