diff --git a/README.md b/README.md
index 8aac0b0..0a731d4 100644
--- a/README.md
+++ b/README.md
@@ -36,6 +36,8 @@ Gitako is **FREE**. If you like it, please
 
 [Feature discussions](https://github.com/EnixCoda/Gitako/discussions) and [bug reports](https://github.com/EnixCoda/Gitako/issues/) are also welcome!
 
+Check out [contributing.md](./contributing.md) if you want to contribute to Gitako directly.
+
 ### About
 
 #### Source of the name and logo?
diff --git a/contributing.md b/contributing.md
new file mode 100644
index 0000000..7b234c2
--- /dev/null
+++ b/contributing.md
@@ -0,0 +1,44 @@
+# Contributing
+
+Thank you if you are trying to contribute!
+
+Note: if you were using Windows, you may need to find alternatives for `make` commands. Or use WSL. I've not tested development on Windows and do not guarantee if it would work.
+
+## Set up development env
+
+1. Clone the repo
+1. Run `make pull-icons` to install dependencies
+1. Run `yarn` to install dependencies
+1. Run `yarn dev` to start the development server, you'll see a `dist` folder appear in the root of this project
+1. Open the extensions page in Chrome, enable developer mode, and load the extension from the `dist` folder
+1. Navigate to repository of your choice and you should see the extension appear
+
+When you modify source code, you need to do either of below to apply your changes:
+
+- (recommended) use [the Extension Reloader extension](https://chrome.google.com/webstore/detail/fimgfedafeadlieiabdeeaodndnlbhid). It could reload all extensions then refresh the page (you need to enable it in its settings).
+- manually reload the extension in the `chrome://extensions` and then refresh your repository page
+
+## Develop with more browsers
+
+Gitako supports more browsers, in order to develop for them, please do the followings.
+
+### Edge:
+
+- Similar to above steps for Chrome
+
+### Firefox:
+
+- run `yarn dev-firefox`
+- a new instance of Firefox will open with Gitako automatically installed
+- navigate to a GitHub repo and you should see the extension appear
+- when you modify source, refresh the tab
+
+### Safari (macOS only):
+
+- run `yarn dev-safari`
+- Open `Safari/Gitako/Gitako.xcodeproj` in Xcode
+- Click the "Run" button
+- Enable developer mode in Safari's preferences
+- Enable Gitako in Safari's preferences
+- Open a Safari tab and visit a GitHub repo, then activate Gitako via Gitako icon next to the address bar
+- when you modify source, click the "Run" button in Xcode and refresh the tab
diff --git a/package.json b/package.json
index d246331..c8e72ff 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
     "prepare": "husky install",
     "dev": "VERSION=dev-v$(node scripts/get-version.js) webpack --watch",
     "dev-safari": "TARGET=safari yarn run dev",
-    "debug-firefox": "web-ext run --source-dir=dist --firefox-profile=firefox-profile --profile-create-if-missing --keep-profile-changes --start-url https://github.com/EnixCoda/Gitako",
+    "dev-firefox": "web-ext run --source-dir=dist --firefox-profile=firefox-profile --profile-create-if-missing --keep-profile-changes --start-url https://github.com/EnixCoda/Gitako",
     "analyze-bundle": "ANALYZE= NODE_ENV=production webpack",
     "postinstall": "node scripts/fix-deps",
     "postversion": "sh scripts/post-version.sh",