Update README

README.md

@@ -2,10 +2,30 @@
 
 ## Setup
 
-Install Emscripten
-https://puddleofcode.com/story/definitive-guide-to-rust-sdl2-and-emscriptem
+- Install Emscripten
+``` 
+# Get the emsdk repo
+git clone https://github.com/emscripten-core/emsdk.git
 
+# Enter that directory
+cd emsdk
+
+# Download and install the latest SDK tools.
+./emsdk install latest
+
+# Make the "latest" SDK "active" for the current user. (writes .emscripten file)
+./emsdk activate latest
+
+# Activate PATH and other environment variables in the current terminal
+source ./emsdk_env.sh
+```
+https://emscripten.org/docs/getting_started/downloads.html
+
+- Compile SDL2:
 ``` 
 $ embuilder.py build sdl2
-$ export EMMAKEN_CFLAGS="-s USE_SDL=2"
 ```
+
+References:
+- https://puddleofcode.com/story/definitive-guide-to-rust-sdl2-and-emscriptem
+