Few steps are needed , log on Zs from the wan side ( assuming you have at least two ethernet interfaces , otherwise log via console ) then change the lan network from the default class C (192.168.0.0/24) to a class B ( 172.16.0.0/16) or class A ( 10.0.0.0/8 ) . Obviously , you can use a subnet of these networks , eg. the 172.16.0.0/23 network will provide you 510 usable host addresses (from 172.16.0.1 to 172.16.1.254) , the ZS ip address could be 172.16.0.1 255.255.254.0 , the dhcp-pool could be 172.16.0.10 -172.16.1.254……is just an example
If you want to use /22 instead of /23 network , then the netmask is 255.255.252.0 , in your case ,network address will be 10.10.0.0 , broadcast address 10.10.3.255 , total 1022 available host addresses , from 10.10.0.1 to 10.10.3.254. Are you sure that you need a so wide network ?? Will be a big , unique, layer2 broadcast domain….