Publish posts in a category

I have a Blog page and on that page, I have 2 sections, “writing and SEO posts” and “Section B”. What I want to do is that when I publish a new post, can choose if the new post is published in the Section “writing and SEO posts” or in the “Section B”. Now, every post goes directly to the Blog page. In the menu, I have a link to “writing and SEO posts” section under the Blog option. “writing and SEO posts” is done like a category, so I thought that if in a post I clicked on that category the post would be published there, but it is not happening and I don’t know how to do it.

Can you help me to understand how I do it? Thanks!

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