In order to configure DHCP Relay simply browse to the Distributed Logical Router that is connected to the network that you want to enable DHCP Relay for and browse to the DHCP Relay tab:
In the DHCP Relay Agents section click the green plus icon and select the network that you want to relay DHCP request packets for and click OK. In my example I'm using the Tenant-01-App-Tier:
Verify all details are correct and click Publish Changes:
Ensure the VM on the network is configured for DHCP, renew the lease and then check the DHCP server to ensure that a lease has been give out:
DHCP Relay has now been configured on the 192.168.1.0/24 network.