It focuses on describing what the whole article has written, which is a summary of the main content of the article.

The key point is to introduce the background knowledge, describe the research object, describe the previous research results and existing problems, and finally draw out the author's improvement/innovation points. The introduction aims to describe the research problems, explain the significance and value of the research, and make readers have a macro understanding of the problems and solutions.

Make a metaphor that may not be appropriate:

If the abstract is compared with the trailer before the film is released, people can get a general understanding of the story of the film.

Introduction is like the opening part of a movie, characters begin to appear and the audience is gradually brought into the scene of the movie story.