Update Using mlem

Using-mlem.md

@@ -37,7 +37,21 @@ The index template will be used to generate an index of all posts. **It must be
     - output_file_name
 - `truncate` [filter][2]; works like a call to String.truncate()
 
-//TODO
+## Writing an entry
+
+To create a new entry you add a markdown file into the src directory. In that file you now have to add frontmatter (A list of keys and values). This is an example of all the needed values:
+
+```markdown
+---
+date: 2024-04-20T20:40:00+02:00
+template: blog.html
+title: Porting libcurl to browser
+---
+```
+
+The date values is an [ISO8601](https://en.wikipedia.org/wiki/ISO_8601) formatted date. The temple is one of the templates which were defined by you. The title is the blog title.
+
+After you added the frontmatter you can write normal markdown like you are used to. 
 
 [1]: https://keats.github.io/tera/docs/
 [2]: https://keats.github.io/tera/docs/#filters