Once there are placeholders in Yeoman, this will automatically rewire your Gruntfile to automatically copy the required files. For now, you have to manually adjust your build step for this to work comfortably.
Trick question. It's not a thing. It's this guy:
Basically, he wears a top hat, lives in your computer, and waits for you to tell him what kind of application you wish to create.
Not every new computer comes with a Yeoman pre-installed. He lives in the npm package repository. You only have to ask for him once, then he packs up and moves into your hard drive. Make sure you clean up, he likes new and shiny things.
$ npm install -g yo
Yeoman travels light. He didn't pack any generators when he moved in. You can think of a generator like a plug-in. You get to choose what type of application you wish to create, such as a Backbone application or even a Chrome extension.
To install generator-appfog from npm, run:
$ npm install -g generator-appfog
Finally, initiate the generator:
$ yo appfog
Yeoman has a heart of gold. He's a person with feelings and opinions, but he's very easy to work with. If you think he's too opinionated, he can be easily convinced.