This might be helpful if you want Devices to have a more friendly host name but still be issued Dynamic IPs (although it does still need populating)
At the bottom of the DHCP conf page in the web gui it says
"Specifying the MAC address is mandatory and only one entry per MAC address is allowed. If the IP address is omitted and a host name is given, the IP address will still be generated dynamically and the specified host name will be used. If the host name is omitted, only a static lease will be added."