Add some primitive building instructions

Author: GarboMuffin

README.md

@@ -2,6 +2,19 @@
 
 Modified version of scratch-paint for TurboWarp
 
+## Building
+
+```bash
+git clone https://github.com/TurboWarp/scratch-paint.git
+npm ci
+npm start
+npm run build
+```
+
+Development playground runs on http://localhost:8078/playground/. Note that http://localhost:8078/ gives you the **built** playground, not the development playground.
+
+For more information, see https://docs.turbowarp.org/development/getting-started
+
 ## License
 
 TurboWarp/scratch-paint is licensed under the GNU General Public License version 3.0. See LICENSE for more information.