ip adress is like home address in network it is like this example 172.45.32.27
there are two types of ip address 1.static 2.dynamic
static never changes it is constant it is your external ip address or public ip you can find it just typing ip address in google and search this will show your ip address
gateway-gateway is the door to the internet
if you have ip like 172.45.32.27 then the gateway will be 172.45.32.1 (in your ip just change the last number after dot to 1 and that will be gateway)
NETMASK -.255.0.0.0 it means that if you have ip address 172.45.32.27 then you can change any last three dots values(45.32.27) to any one like 12.78.154 here 255 means it limits the ip from 1 to 255
if you are in LAN connection you can got to control panel network setting there you can find your ip address gateway subnet mask and DNS
Another method
am going to tell you for two types of internet
1.static ip
2.Dynamic DHCP
static ip is the ip address that never change that is staic