Instructions for replacing the filter on a Brita pitcher are published in the Brita Pitcher User Guide found in the FAQs of the Product Support section on Brita.com. Instructions are also found in the User Guide included in the box with the Brita pitcher when it is purchased.
The Brita Pitcher User Guide contains general replacement instructions for all Brita pitchers. The Product Support FAQ also includes a filter-replacement how-to question that is answered with basic four-step instructions for prepping and installing a new filter. Filter replacement instructions are also found in the package with new replacement filters for the Brita pitcher.