Update assets/README.md w/ new install instructions

assets/README.md

@@ -3,9 +3,7 @@
 The folder "assets" will be processed by the js library Webpack Encore and the result
 will be saved in public/build folder.
 
-In order to accomplish this task there are some prerequisites.
+In order to accomplish this task, we first need to install yarn. Yarn is a JavaScript dependencies manager similar to Bower (that we also used for development in Chamilo 1.11.x), only that Bower seems to be deprecated now.
-
-- Install yarn
 
 Follow the installation instructions here https://yarnpkg.com/en/docs/install
 
@@ -14,25 +12,32 @@ After the installation run this command in the Chamilo root:
 ``yarn install``
 
 yarn will read the dependencies in the **packages.json** file and save the dependencies in the
-'node_modules' folder (this must not be committed to the Chamilo repository).
+'node_modules' folder (which must **NOT** be committed** to the Chamilo repository).
 
 # Configuring Encore/Webpack
 
+Webpack takes CSS, JS and other files and generates tidy single-files to attach to your web package.
+
 The behaviour of how packages will be processed is describe here: "webpack.config.js".
 
-In order to process that file you can run:
+In order to process that file you will first need to edit webpack.config.js (around line 8) and decide whether .setPublicPath() shoud be configured for a subdirectory or a FQDN (Fully Qualified Domain Name). Leave as is for subdirectories or comment and uncomment the following .setPublicPath() for an FQDN.
 
-Then to finally create the public/build contents you can run:
+If the public/js/fos_js_routes.json file does not exist (or if you're in doubt about the version of your PHP libs), run:
+```
+composer update
+bin/console fos:js-routing:dump --format=json --target=public/js/fos_js_routes.json
+```
 
-Compiles assets once:
+Then, to create the public/build contents, run one of the following commands:
+To compile assets just once:
 
 ``yarn run encore dev``
 
-Recompile assets automatically when files change
+To recompile assets automatically when files change:
 
 ``yarn run encore dev --watch``
 
-Compile assets, but also minify & optimize them
+To compile assets and minify & optimize them:
 
 ``yarn run encore production``