# Exercise 2: Add a new file to the table of contents

Let's continue by adding one additional step. Let's add a file to the table of contents! the `_toc.yml` contains a list of all the files to be shown in your book-website. Let's add a file which is not in the table of contents yet!

::::::{topic} Exercise objective
Can you add the file named `file_to_be_added_to_toc.md` to the book website?
::::::

1. Go to the {octicon}`code;1em` `Code` - `Book` directory of your GitHub repository and find the location of `file_to_be_added_to_toc.md`
2. Go to the the file `book/_toc.yml` on your GitHub repository - {octicon}`code;1em` `Code` - `Book` - `_toc.yml` - {octicon}`pencil;1em` `Edit this file`
3. Add `file_to_be_added_to_toc.md` as a second subpage under `some_content/overview.md`. `some_content/text_and_code.ipynb` is the first subpage.

````{admonition} Need some help?
:class: tip, dropdown
Your `_toc.yml` should look like
```yaml
format: jb-book
root: intro.md

parts:
  - caption: Contents
    chapters:
    - file: some_content/overview.md
      sections:
      - file: some_content/text_and_code.ipynb
      - file: file_to_be_added_to_toc.md
    - file: exercises/exercises
      sections:
      - file: exercises/001.md
      - file: exercises/002.md
      - file: exercises/003.md
      - file: exercises/004.md
      - file: exercises/005.md
      - file: exercises/006.md
    - file: references.md
    - file: changelog.md
    - file: credits.md
```
````
4. Click `Commit changes`
5. Add a message and description of your change
6. Select `Commit directly to the main branch` (this adds your change your change to the default version instead of making a new one)
7. Click `Commit changes`
8. Go to {octicon}`play;1em` `Actions` - The most recent workflow run `Update _toc.yml / the commit message of the commit you just made` - Wait for it to finish - In the summary, click on the link of your book shown in the table `Branches deployed` and under `Primary book at root` (getting bored of waiting? There'll be exercising on doing this locally which prevents you from waiting)
9. Do you see your change? If you don't see it click `CTRL`+`F5`/`Control`+`F5`to refresh the page.

```{admonition} Check your understanding
:class: note

Before moving on to the next exercise, make sure you understand the following:
- Are all files in the repository added to the website?
- What is the purpose of the `_toc.yml` file?
- What happens if a file is not listed in the `_toc.yml`?
- How can you verify that your changes to `_toc.yml` were successful?
- Does the structure of the `_toc.yml` file need to match the directory structure of the repository?
```