Many Keurig instruction manuals are available online in PDF form. From the support page at Keurig.com, select the brewer model you own. The user guide for each model is located in the General Brewer Information section.
You may need the model number of your brewer to locate its user manual. Usually, the model number is on the bottom of the brewer. Some Keurig models have both a user guide, providing in-depth information about the product, and a quick guide available on the website. The quick guide contains general information, recipes and helpful hints, but it does not contain information concerning product mechanics.