[README] updated for the main lib & example

README.md

@@ -7,11 +7,10 @@ A domain specific language will come to help scientist to model complex systems.
 ## Building
 
 ``` sh
+# We use nix for building things
+nix-shell
+# Install nodejs dependencies
+yarn
+# Install deps & build the PS project
 yarn spago build
 ```
-
-## Serving
-
-``` sh
-nvm use --lts
-yarn parcel index.html

example/README.md

@@ -3,13 +3,14 @@
 ## Building
 
 ``` sh
+nix-shell
 yarn
-yarn spago build
 yarn spago bundle-app
 ```
 
 ## Serving
 
 ``` sh
+nvm use --lts
 yarn parcel index.html
 ```