-make sure the machine has got isc-dhcp-server installed
-read the different files and ADD (no copy!) the parts you need
to the proper locations
/etc/inetd.conf
/usr/local/etc/dhcpd.conf

-(re)start servers, rebooting the machine is much faster ;-)
/usr/local/etc/rc.d/isc-dhcpd.sh restart
/etc/rc.d/inetd restart
/etc/rc.d/ipfw restart

Cheerz,
Rick van der Zwet <rick@wirelessleiden.nl>