How to build a website like this!

After reading the first comments I feel like crying.
People who claim that this can be built with bootstrap or CSS are a total waste of time.

I did not delve too deeply into the website, but it seems to be something that providers use to advertise their services.

This can be achieved in several ways, through a CMS platform already built as Joomla & WordPress & Concrete, whatever.
Or this could be built from scratch with PHP, Vanilla or Framwork, that's your choice.

If you are interested in doing something similar but do not have much experience in web development, I suggest you take a look at the basic WordPress tutorials, how to create a topic from scratch, and that will give you some notions of PHP as well.

After that, you can move on to more complex things that require deeper background knowledge.

one. [Creating a basic theme]
two. [Developing various functions for basic usage]
3. [Taking care of the UI]