I need an explanation for these commands used on Cisco packet tracer.

Router Configuration Commands used in lab:

Router>enable

Router#configure t

Router(config)#hostname R01

R01(config)#interface fastEthernet 0/0

R01(config-subif)#no shutdown

Enters the fastEthernet0/0 interface of the the router.

R01(config)#interface fastEthernet 0/0.10

R01(config-subif)#ip address 192.168.10.254 255.255.255.0\

R01(config-subif)#encapsulation dot1Q 10

R01(config-subif)#no shutdown

R01(config)#interface fastEthernet 0/0.20

R01(config-subif)#ip address 192.168.20.254 255.255.255.0

R01(config-subif)#encapsulation dot1Q 20

R01(config-subif)#no shutdown

R01(config)#interface fastEthernet 0/0.30

R01(config-subif)#ip address 192.168.30.254 255.255.255.0

R01(config-subif)#encapsulation dot1Q 30

R01(config-subif)#no shutdown

R01(config)#interface serial 2/0

R01(config-if)#ip address 10.0.0.1 255.0.0.0

R01(config-if)#clock rate 128000

R01(config-if)#bandwidth 128

R01(config-if)#no shutdown

R01(config)#ip dhcp pool Vlan10

R01(dhcp-config)#network 192.168.10.0 255.255.255.0

R01(dhcp-config)#default-router 192.168.10.254

R01(dhcp-config)#dns-server 11.11.11.11

R01(config)#ip dhcp pool Vlan20

R01(dhcp-config)#network 192.168.20.0 255.255.255.0

R01(dhcp-config)#default-router 192.168.20.254

R01(dhcp-config)#dns-server 11.11.11.11

R01(config)#ip route 0.0.0.0 0.0.0.0 serial 2/0