Updated README to split mechanisms from puzzles, and add more instructions.

Author: JoelCodes

README.md

@@ -16,8 +16,21 @@ For these exercises, you only need to go the `/answers` directory and implement
 
 Or, you can run only the test suites for any exercise using the commands below.
 
+> Quick tip:  To run any of the exercises below in watch mode, add `-- --watch`, (e.g. `npm run making-promises -- --watch`)
+
+You are free to look at any of the tests for guidance, but don't change them.
+
 ## Outline
 
+### The Promise Toolbox
+
+These exercises are all about learning the mechanisms that we can use to create, transform, and combine promises.
+
 `npm run making-promises` - Create promises with Promise.resolve, Promise.reject, and the Promise constructor.
 `npm run and-then` - Use `.then(cb)` and `.catch(cb)` to consume the output of promises, as well as to transform and chain async processes.
+
+### Promise Puzzles
+
+Now it's time to use the tricks from above to solve some problems.
+
 `npm run callbacks` - Turn callback-centric functions into promise-centric functions.