nopCommerce Website sections

Does anyone knows how to add section into my pages?

example, in my home page you will see a section with introduction text with grey background color
below introduction you will get a about us section with blue color.
if anyone knows how to do that let me know asap please.

Some sections like your Introduction are Topics.  (e.g. is your introduction text in Topic named HomepageText?)

There are standard sections on the home page like HomePageBestSellers, HomePageCategories, etc.

Related to the above home page sections are Widget Zones:
HomepageTop
HomepageBeforeCategories
HomepageBeforeProducts
HomepageBeforeBestSellers
HomepageBeforeNews
HomepageBeforePoll
HomepageBottom

However, the widget plugin must "subscribe" to the Zone(s).

With minor "coding" of this page:
   \Views\Home\Index.cshtml
You could introduce additional "sections".

You will see in there how the Topic named HomepageText is invoked where it is:
@await Component.InvokeAsync(typeof(TopicBlockViewComponent), new { systemName = "HomepageText" })

So, if you Add a new Topic, and give it a System name (in Display Section), you could edit the above mentioned Index.cshtml file, and insert another @await Component.InvokeAsync(...) in there.