How to find articles, Rewrite articles and what are rules I should follow?

I want to start blogging, and I found a lot of articles on the net, and I always wondered how did they find that? Or know about that topic to write about it.

And what If you find a great article you found on a website? I know you could just copy/paste the whole thing and say “found on [insert site]” But I don’t like doing that. am I able to review. rewrite the article? If so, can you give me any tips on how to write a “good” article.

Also any rules I should know?

I really wish to learn this, thanks for everyone who answers