Let's build something.
You cook excellent tiffin. People keep asking if they can order online. So you are going to build TiffinBox the way real companies do it: starting almost embarrassingly simple, and adding machinery only when a real problem forces it.
Right now your product is one thing: a browser with nothing to show.
One page, one machine.
You write a single page, your menu, your phone number, and put it on a server: a computer that never sleeps, waiting to hand that page to anyone who asks.
This is a real setup. Thousands of businesses run on exactly this and nothing more.
But how do people find it?
Your server has an address, a string of numbers. Nobody remembers numbers. So you buy the name tiffinbox.com, and DNS keeps the mapping: when a browser asks for your name, DNS answers with the number. HTTPS keeps the connection private.
Phase 1 complete. You are on the internet.
You worked through Phase 1: put a page on the internet. 10 new concepts joined your architecture along the way.
Next problem: 500 items, prices change daily, things sell out by noon. You cannot hand-edit a page every time.