Fixed IP on AP side doesn't work

[Clox1800]

Hi, l would like to create on AP side of ESP32 NAT Router a network based on fixed IP address for the devices. I don't find any command to create theses DHCP rules. On top of that, as my devices are ESPEasy based, I tried to allocate a fixed IP address while configuring and loading them. No results, NAT Router allocates a variable address. I would like some advice ... Thanks.