To start your coding journey particularly being a web developer, below are a simplified details of some essential setup you must have.
Web Browser
A web browser should not be included in this list but i did because i assume i am communication to an absolute beginner, so you must download a modern web browser like chrome for the preview of your website.
https://www.google.com/chrome/
Code Editor
To write your code, you need to download and install a code editor, as a beginner I will not state many option, just proceed and install VS code via the link below.
https://code.visualstudio.com/download
VS code Extension
As much as i am trying to keep things short and simple, I will like to include this extension to keep your page auto refreshing as you write your code.
Install Live Server with the below link.
https://marketplace.visualstudio.com/items?itemName=ritwickdey.LiveServer
Above is a basic thing you need to get started, then other will be added as needed.