Open up the newly generated application in either your command line or a file manager. In the newly generated directory, you'll see a number of few files and a number of directories. The three directories we're most interested in this point are:
app - Your application lives here. All models, views and controllers are contained within the files and directories in the app directory. Of particular interest is the app.rb file, this is where we'll be putting our actions for now.
public - The files in this directory get served without going through any of the application controllers. Images, stylesheets, etc can go here.
config - Config files go here. Of particular interest is database.rb, where you can configure your databases. If you're using MySQL, you might need to change this file to reflect your MySQL server setup. If you're using Sqlite, you can most likely leave this as the default.