How do you remove wiper arm from catera 2001?

Assuming that you mean "wiper blade" (blade and frame) which are replaced often rather than "wiper arm" (piece from the spindle at the hood to the wiper blade) which are rarely ever replaced, the 2001 Toyota 4Runner has the most common hook-end wiper arms. See sources and related links below for installation videos. Also, purchase the replacement blades first and there will be additional instructions/illustrations on the replacement packages. Locate and press the tab or button where the wiper blade is inserted into the hook of the wiper arm and pull wiper blade out of hook. You may have to rotate and flex the blade to make enough clearance for the hook to pass through.