How to assign issued ip to mac address in DD-WRT?

Question

network hardware

Put on WR740N DD-WRT
Disabled issuance of DHCP because I do not need to issue all ip addresses, but only those who know the gateway will prescribe itself.
But you need to issue IP to 2-3 devices.
At the same time, in the stock firmware it was possible to configure to issue IP via DHCP only to those devices whose MAC addresses are registered in the settings.
How to do the same in DD-WRT so that DHCP issues IPs only to the devices I need