QOS with IP phones

[Julien]

Hi Guys,
i have OPNsense on a LAB " Planning to go soon on production ".
on the LAB i have 3 VALNS, 1.2.3
VLANS 3 is VOICE Vlan and want to configure QOS on the firewall side.
can't seem to find this option somewhere on the file, i've found the traffic shapping.
is this the way to configure the QOS ? if yes can you please explain how ?