Google Cloud Print will require that you have an active gmail account and that you have set up cloud print to handle certain printers. Most likely the printers in your home that your computers have access to, will be the ones that you see in the app first. If you have a Cloud Print-enabled printer like an Epson Artisan 730, there is a firmware update available to allow cloud printing directly.
Cloud Print will allow you to access any printers that are turned-on and have been connected to a computer that has Google Chrome installed and recognized by Cloud Print. By default you should be able to print to PDF, save to Google Drive, or Print to a local FedEx Office. After these defaults, any other printers connected to any of the computers that you have run Chrome with Cloud Print enabled, should be available to you.