DHCP automatically assigns IP command configuration

The router R3 acts as a server to assign IP addresses to PC3 and PC4:

[r3] dhcp enable-----Enable the DHCP server
[r3] ip pool ?
STRING<1-64> Pool name
[r3] ip pool aaa---- -Create an address pool (aaa is the name of the address pool)
[r3-ip-pool-aaa]network 192.168.4.0 mask 24-----Write the address of the 4.0 network segment in the address pool (DHCP server can request IP The host at the address issued the IP address of the 4.0 network segment)
[r3-ip-pool-aaa]gateway-list 192.168.4.1----gateway address
[r3-ip-pool-aaa]dns-list 114.114.114.114-- --dns address
[r3-ip-pool-aaa]q
[r3]inter g0/0/1
[r3-GigabitEthernet0/0/1]dhcp select global----Enter the interface of the router connected to the PC, all DHCP according to the global configuration rules