I'm doing like this:
I had created a DHCP on the lan 192.168.1.0/24 with the DHCP from 192.168.1.100 to 192.168.1.254
All devices are DHCP client ( except the gatway of course).
For the client I want a reserved IP, the first time, In the DHCP, I "fix" the ip with a number under 100.
I let all clients computers, tablets, smarphones in "free" DHCP
And I let router, AP and printer in "fixed" DHCP like this.