Update README.md

README.md

@@ -34,7 +34,14 @@ Open the `package.json` file and change the `name`, `description` and `author` f
 The `name` should be unique and you should use a namespace (like how I use `@sebkolind` for my packages),
 `author` is you and `description` is a short summary of what your package is about.
 
-### Start building
+## Start building
+
+The package is setup with a `lib` folder which contains all your package code.
+Inside the lib folder is a `main.ts` file. This is the entry point, meaning that
+this will be the place to export code that can be used by consumers of your library.
+
+The folder `__tests__` holds all your unit tests. When you run `npm run test` the files ending with
+`.test.ts` will run.
 
 ```sh