Setup DHCP Relay VyOS

#set service dhcp-relay interface YOUR_INTERFACE
Or,
#set service dhcp-relay server YOUR_SERVER_IP
#commit
#save

Reference:
https://docs.vyos.io/en/equuleus/configuration/service/dhcp-relay.html

Set an IP on an Interface in VyOS

#set interfaces ethernet YOUR_INTERFACE address YOUR_IP|dhcp|dhcpv6
#set interfaces ethernet YOUR_INTERFACE description DESCRIPTION_FOR_INTERFACE
#set interfaces ethernet YOUR_INTERFACE disable
#set interfaces ethernet YOUR_INTERFACE enable
#commit
#save

Reference:
https://docs.vyos.io/en/equuleus/configuration/interfaces/ethernet.html