How much should everything be a component when building a React app?

Question

React

Good day to all :) I'm just starting to understand React and here is such a, probably a little silly, question:
How to properly split into components in HTML? what I mean: initially leave only 1 tag in html and render the whole application there or split it on the page into, for example: id="header", id="content", id="sidebar", etc... where will these components be rendered? how right? Thank you)

Answer 1

the entire application needs to be rendered into one tag.
The component that you will render into it will contain child components:
id="header", id="content", id="sidebar"