diff --git a/docs/CONTRIBUTING.md b/docs/CONTRIBUTING.md
index 88db8553..713b30bc 100644
--- a/docs/CONTRIBUTING.md
+++ b/docs/CONTRIBUTING.md
@@ -21,10 +21,30 @@ git clone https://github.com/resin-io/etcher
 cd etcher
 ```
 
+- Configure NPM.
+
+In UNIX based operating systems:
+
+```sh
+export npm_config_disturl=https://atom.io/download/atom-shell
+export npm_config_target=<ELECTRON_VERSION>
+export npm_config_runtime=electron
+```
+
+In Windows:
+
+```sh
+set npm_config_disturl=https://atom.io/download/atom-shell
+set npm_config_target=<ELECTRON_VERSION>
+set npm_config_runtime=electron
+```
+
+You can find the appropriate electron version in the `devDependencies['electron-prebuilt']` field in `package.json`.
+
 - Install dependencies.
 
 ```sh
-npm install
+npm install --build-from-source
 bower install
 ```