docs(contributing): add 'how to add new presets' guide

CONTRIBUTING.md

@@ -6,12 +6,17 @@ Reading and following these guidelines will help us make the contribution proces
 
 ## Quicklinks
 
+<!-- vim-markdown-toc GFM -->
+
 - [Code of Conduct](#code-of-conduct)
 - [Getting Started](#getting-started)
   - [Issues](#issues)
   - [Pull Requests](#pull-requests)
+  - [How to add new presets?](#how-to-add-new-presets)
 - [License](#license)
 
+<!-- vim-markdown-toc -->
+
 ## Code of Conduct
 
 We take our open source community seriously and hold ourselves and other contributors to high standards of communication. By participating and contributing to this project, you agree to uphold our [Code of Conduct](./CODE_OF_CONDUCT.md).
@@ -90,6 +95,20 @@ cargo clippy --verbose -- -D warnings
 
 11. The PR will be merged once you have the sign-off of the repository owners.
 
+### How to add new presets?
+
+I'm glad you asked!
+
+1. Add your sound files to [`sounds/`](sounds/). Currently, only the [MP3](https://en.wikipedia.org/wiki/MP3) format is supported.
+
+2. Configure the preset in [`config/daktilo.toml`](./config/daktilo.toml). See [adding custom presets](README.md#adding-custom-presets).
+
+3. Update [`README.md`](README.md) about the availability of this new preset.
+
+4. Create a pull request. See above.
+
+5. Profit.
+
 ## License
 
 By contributing, you agree that your contributions will be licensed under [The MIT License](./LICENSE-MIT) or [Apache License 2.0](./LICENSE-APACHE).

README.md

@@ -42,6 +42,7 @@ Now you can recreate this moment without the actual need for a physical typewrit
 - [Similar Projects](#similar-projects)
 - [Acknowledgements](#acknowledgements)
 - [Donations](#donations)
+- [Contributing](#contributing)
 - [License](#license)
 - [Copyright](#copyright)
 
@@ -289,6 +290,12 @@ Kudos! 👾
 
 If you find **daktilo** and/or other projects on my [GitHub](https://github.com/orhun) useful, consider supporting me on [GitHub Sponsors](https://github.com/sponsors/orhun) or [becoming a patron](https://www.patreon.com/join/orhunp)!
 
+## Contributing
+
+See our [Contribution Guide](./CONTRIBUTING.md) and please follow the [Code of Conduct](./CODE_OF_CONDUCT.md) in all your interactions with the project.
+
+Also, see how you can add new presets [here](CONTRIBUTING.md#how-to-add-new-presets).
+
 ## License
 
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg?style=flat&logo=GitHub&labelColor=1D272B&color=819188&logoColor=white)](./LICENSE-MIT)