diff --git a/README.md b/README.md
index 18410bd..64f49d9 100644
--- a/README.md
+++ b/README.md
@@ -4,4 +4,27 @@ This is the GitHub repository for the Radis - Radiation Main Site. The Main Site
 
 The documentation of the Radis project is found at [radis.readthedocs.io/](https://radis.readthedocs.io/).
 
-The website uses the template from the excellent [EinsteinPy project](https://einsteinpy.org/). Check them out!
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+The website uses the template from the excellent [EinsteinPy project](https://einsteinpy.org/). Check them out!
+
+## Running locally
+
+**With Docker (easiest):**
+```bash
+make serve
+```
+
+**Without Docker** — install Ruby first:
+
+| OS | Command |
+|---|---|
+| macOS | `brew install ruby` |
+| Ubuntu/Debian | `sudo apt install ruby-full build-essential zlib1g-dev` |
+| Windows | [RubyInstaller](https://rubyinstaller.org/) (include DevKit) |
+
+Then:
+```bash
+gem install jekyll bundler jekyll-sitemap
+jekyll serve
+```
+
+Open [http://localhost:4000](http://localhost:4000). Jekyll auto-reloads on file changes.
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