Okay, here's the deal, arjun_teen!!! It's not too complicated once you get it, honestly.
Espresso: This is the base for everything! A concentrated shot of coffee, usually 1-2 oz. Very strong, no milk at all! Just pure coffee flavor, made with pressure through finely ground beans... yum!!!
Americano: Easy peasy! Take your espresso shot, or two shots, and add hot water to it. The ratio is usually 1:2 or 1:3 espresso to hot water. It's like a drip coffee, but with that espresso kick. So good for a morning boost! This one is super simple to make at home!!
Cappuccino: This is where milk gets involved, big time! You'll need one-third espresso, one-third steamed milk, and one-third foamed milk. Key is that thick, airy foam on top! It's so frothy and lovely... sometimes I add a little sprinkle of cocoa powder, just for fun :) You'll love teh foam!
Latte: Oh, the latte! It's mostly milk, honey. One-third espresso, but then two-thirds steamed milk, and only a very thin layer of foam on top, if any! It's smoother, creamier, and a bit milder than a cappuccino. So comforting on a cold day.
Hope this helps you with your home brewing adventures!!! It's all about experimentation, don't you think?? Have fun, sweetie!