How to service break calipers?

ok so i know like nothing about cars and my uncle said if i could find out from searching on the web and stuff how to do this hell give me 20 quid so here goes he said something like he needs to find out how to bring back the brake calipers or something like that to change the brake pads and he said you need to connect a computer to it to be able to do it so it must be a new car i don't know sorry if im not making any sense as i know nothing about cars and help will be appreciated