Setting up Device Tracker when using dnsmasq

Hello cogniscenti,
I am happily using dnsmasq on a separate Raspberry Pi 3 to run as the DHCP and DNS server. HA is happily running in a container on a Raspberry Pi 4.
Please could someone tell me how I can set up a device tracker in HA to use the DHCP server to know which devices are on the network? I’ve had a look on the forum and there is a bit about PiHole and a bit about dnsmasq running in Hassio but I can’t find what I am looking for. Many apologies if this has been dealt with already, please can you point me to the info if it has.
TIA,
PS