Hi Yaniv,
The new Javascript API is based on React & TypeScript.
I don't know about your background in programming, but assuming you do have some, consider the Render function to be the main method / entry point of a React component.
Once the code is "compiled", the output of HTML is done through the Render function and it's always required.
The HTML tags you see inside the Render method is not really HTML tags.. it's JSX, which is also part of the way you code in React.
I highly suggest you find some quick and basic videos on how to work with React, to understand better about the technology. It will make much more sense and be less "painful" to learn by experimenting
These are only the building blocks, but the more complex stuff comes when learning about state management of components when working with React - and that's where the magic of React comes in place. Online tutorials will teach you much better about it than me.
Shay.
Shay