This is a guide for printing from a Chrome Device.
To see how to add printers to a Windows device instead, please see the following guide: How do I add printers?
1) Log into your ChromeOS device (Chromebook or ChromeBox)
2) Install the "Mobility Print" Chrome extension. Follow this guide: How do I install Chrome Extensions?
3) Attempt to print your Document. This could be done in several ways depending on what you are printing and from where. Common ways are clicking the icon that looks like a printer (if there is one), Clicking the three-dot menu button in the top-right and selecting "Print", or pressing Ctrl+P on your keyboard.
4) Once the Print Preview Window opens, click in the "Destination" drop down, then click "See More..."
5) WAIT! It may take up to a minute for the printers to show up the first time. When they do, you will see a list like the one below. Click on the printer you'd like to print to. You can also search for a printer. (Note: For Stapling, Eco-Stapling, and Holepunch options, look for the printers in the list that have (Holepunch) (Staple) etc. in the name.)
6) Your printer will now be selected. Click "More Settings" if needed to reveal additional settings, as shown below.
7) Once you are happy with your settings, click "Print"
Related Questions:
How do I add printers to my Chromebook?
How do I add printers to a Chromebox?
How do I print from a Chromebox?
How do I install a printer?