docs: update blog post creation guide

Author: satnaing

src/data/blog/adding-new-post.md

@@ -1,7 +1,7 @@
 ---
 author: Sat Naing
 pubDatetime: 2022-09-23T15:22:00Z
-modDatetime: 2025-03-08T07:46:00.619Z
+modDatetime: 2025-03-17T17:41:19.776Z
 title: Adding new posts in AstroPaper theme
 slug: adding-new-posts-in-astropaper-theme
 featured: true
@@ -15,8 +15,43 @@ description:
 
 Here are some rules/recommendations, tips & ticks for creating new posts in AstroPaper blog theme.
 
+<figure>
+  <img
+    src="https://images.pexels.com/photos/159618/still-life-school-retro-ink-159618.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1"
+    alt="Free Classic wooden desk with writing materials, vintage clock, and a leather bag. Stock Photo"
+  />
+    <figcaption class="text-center">
+    Photo by <a href="https://www.pexels.com/photo/brown-wooden-desk-159618/">Pixabay</a>
+  </figcaption>
+</figure>
+
 ## Table of contents
 
+## Creating a Blog Post
+
+To write a new blog post, create a markdown file inside the `src/data/blog/` directory.
+
+> Prior to AstroPaper v5.1.0, all blog posts had to be in `src/data/blog/`, meaning you couldn't organize them into subdirectories.
+
+Starting from AstroPaper v5.1.0, you can now organize blog posts into subdirectories, making it easier to manage your content.
+
+For example, if you want to group posts under `2025`, you can place them in `src/data/blog/2025/`. This also affects the post URL, so `src/data/blog/2025/example-post.md` will be available at `/posts/2025/example-post`.
+
+If you don’t want subdirectories to affect the post URL, just prefix the folder name with an underscore `_`.
+
+```bash
+# Example: blog post structure and URLs
+src/data/blog/very-first-post.md          -> mysite.com/posts/very-first-post
+src/data/blog/2025/example-post.md        -> mysite.com/posts/2025/example-post
+src/data/blog/_2026/another-post.md       -> mysite.com/posts/another-post
+src/data/blog/docs/_legacy/how-to.md      -> mysite.com/docs/how-to
+src/data/blog/Example Dir/Dummy Post.md   -> mysite.com/example-dir/dummy-post
+```
+
+> 💡 Tip: You can override a blog post’s slug in the frontmatter as well. See the next section for more details.
+
+If the subdirectory URL doesn’t appear in the build output, remove node_modules, reinstall packages, and then rebuild.
+
 ## Frontmatter
 
 Frontmatter is the main place to store some important information about the blog post (article). Frontmatter lies at the top of the article and is written in YAML format. Read more about frontmatter and its usage in [astro documentation](https://docs.astro.build/en/guides/markdown-content/).