diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..929e1ca
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,73 @@
+# Contributing
+
+When contributing to this repository, please first discuss the change you wish to make via issue,
+email, or any other method with the owners of this repository before making a change.
+
+Please note we have a code of conduct, please follow it in all your interactions with the project.
+
+## Pull Request Process
+
+Pull requests are always welcome.
+
+1. Fork this repository
+2. Create branch: `git checkout -b my-new-feature`
+3. Test `docx-core`: `make test && make lint`
+4. Update snapshot test result (If needed): `cargo-insta review`
+5. Test `docx-wasm`: `cd docx-wasm && yarn install && yarn test`
+6. Update snapshot test result (If needed): `cd docx-wasm & yarn test -- --updateSnapshot`
+7. Push: `git push origin my-new-feature`
+8. Send PR :)
+
+## Code of Conduct
+
+### Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as
+contributors and maintainers pledge to making participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, gender identity and expression, level of experience,
+nationality, personal appearance, race, religion, or sexual identity and
+orientation.
+
+### Our Standards
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery and unwelcome sexual attention or
+advances
+* Trolling, insulting/derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or electronic
+  address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+### Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable
+behavior and are expected to take appropriate and fair corrective action in
+response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or
+reject comments, commits, code, wiki edits, issues, and other contributions
+that are not aligned to this Code of Conduct, or to ban temporarily or
+permanently any contributor for other behaviors that they deem inappropriate,
+threatening, offensive, or harmful.
+
+### Scope
+
+This Code of Conduct applies both within project spaces and in public spaces
+when an individual is representing the project or its community. Examples of
+representing a project or community include using an official project e-mail
+address, posting via an official social media account, or acting as an appointed
+representative at an online or offline event. Representation of a project may be
+further defined and clarified by project maintainers.
diff --git a/README.md b/README.md
index 7f7f01d..120d9e0 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ docx-rs = "0.2"
 ### Browser/Node.js
 
 ```
-yarn add docx-wasm
+$ yarn add docx-wasm
 ```
 
 ## Example
@@ -84,6 +84,69 @@ writeFileSync("hello.docx", buffer);
 - [Image](https://github.com/bokuweb/docx-rs/blob/master/docx-core/examples/image_inline.rs)
 - [History](https://github.com/bokuweb/docx-rs/blob/master/docx-core/examples/history.rs)
 
+## Development
+
+### Requirements
+
+- Node.js 16+
+- yarn 1+
+- wasm-pack (https://rustwasm.github.io/wasm-pack/)
+- insta (https://github.com/mitsuhiko/insta)
+
+### Examples
+
+You can run example with following code.
+Please see `examples` directory.
+
+``` sh
+$ cargo run --example [EXAMPLE_NAME]
+```
+
+For Example if you want to run `hello` example.
+Please run following command.
+
+``` sh
+$ cargo run --example hello
+```
+
+So you can see output file in output directory.
+
+### Testing
+
+#### Rust
+
+Please run following command.
+
+```
+make lint && make test
+```
+
+If snapshot testing is failed, fix code or update snapshot files. (See https://insta.rs/).
+
+```
+$ cargo-insta review
+```
+
+Then re run test.
+
+```
+$ make test
+```
+
+#### Wasm
+
+Please run following command.
+
+```
+$ cd docx-wasm && yarn install && yarn test
+```
+
+If snapshot testing is failed, fix code or update snapshot files. (See https://jestjs.io/docs/snapshot-testing).
+
+```
+$ yarn test -- --updateSnapshot
+```
+
 ## Features
 
 - [x] Paragraph