diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..d1c1dbe
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+node_modules
+bundle.js
diff --git a/README.md b/README.md
index a0bb242..51b2d8b 100644
--- a/README.md
+++ b/README.md
@@ -5,11 +5,20 @@ A simple timer for extracting expressos.
## Usage
-Just open `index.html` with your browser.
+```
+npm install
+npm run build
+```
+
+Then, just open `index.html` with your browser.
## License
+Tick sound from https://soundbible.com/2044-Tick.html.
+
+End sound from https://soundbible.com/1630-Computer-Magic.html.
+
Code published under an MIT license.
```
diff --git a/end.mp3 b/end.mp3
new file mode 100644
index 0000000..f86c144
Binary files /dev/null and b/end.mp3 differ
diff --git a/index.html b/index.html
index f47d0a8..05e3724 100644
--- a/index.html
+++ b/index.html
@@ -3,7 +3,6 @@