They're all the same! And it's a feature, not a bug!
Ask yourself: what is the purpose of an article, or, as I'll call it from here on, a paper? Sure, it could be vanity, or someone's boss asked them to write something. But surely
The main purpose of a paper is to convey a new idea, and show that it has merit.
That's it! And everything else should serve that purpose. It turns out that over the last few hundreds of years, Science has converged to a standard format to convey ideas and show their merit. Enter, the standard structure of a paper!
Title. This is marketing. Make something snappy that is interesting, but also explains what this is about. 2 to 8 words.
Abstract. (Executive summary) There are different views on this, but for me it's an executive summary, not only a teaser. Put the why, how, what, and results in here. 200-400 words.
Introduction. (Why are you doing this?) Explain why you wrote the paper. What is the problem you are solving? What is the big picture? Which other ideas were there, and what specific question did they not answer? How are you going to solve this? 1-3 pages.
Methods. (How did you do it?) Which tools and theories do you use in this paper? How do you know they work? A few paragraphs to a few pages, depends on what you're doing!.
Results. (What did you find?) What does your analysis show? Neutral, objective discussion of the findings. This is the core of the paper, see how much space you need (and the journal gives you) to document everything.
[Discussion] (What does it mean?) Not always there, but this is the spot to interpret your results rather than just report them. Maybe 1-2 pages, if necessary.
Conclusions (What did you learn?) Did something surprise you? If there are 3 points you would like the reader to realize, what are they? 3-5 short paragraphs or bullet points, ordered in decreasing importance.
Of course there are intricacies to each of these points in turn, but this is a good starter to get you oriented!