Struggling with one DHCP server, and multiple VLANs on ICX 7150 Switch image

I have one DHCP server in default VLAN.  I have multiple VLAN (voice) and I want the ports on the VLAN to grab dhcp addresses from additional scopes.  I know that I need to use IP Helper, but all instructions refer to an IP address assigned to your VLAN.  I don’t see where to do that…only IP address assigned is the siwtches IP.