Buying a standing desk is the easy part. Setting it up so it actually helps your body, rather than trading back pain for wrist pain, takes a few minutes of adjustment that most people skip.
Start with your elbows The golden rule is simple: when you are standing comfortably with relaxed shoulders, your elbows should bend at roughly 90 degrees with your forearms parallel to the floor. Raise or lower the desk until the keyboard sits right at that height. Your wrists should stay flat and neutral, never bent up to reach the keys.
Then fix your monitor The top of your screen should sit at or just below eye level, about an arm's length away. If you find yourself tilting your head down, raise the monitor with an arm or a stand. Looking down for hours is a fast route to neck strain.
Don't stand all day The goal is movement, not heroics. Standing rigidly for eight hours is as hard on your body as sitting all day. Aim to alternate: a common starting point is roughly 30 minutes standing for every hour or so, then adjust to what feels good.
Small additions that help a lot - An anti-fatigue mat takes pressure off your feet and lower back - Supportive shoes or going barefoot beats hard floors in socks - A footrest lets you shift your weight and engage different muscles - Move the desk down and sit the moment you feel fatigue creeping in
Get the elbow and monitor heights right first, then build the standing habit gradually. The desk only delivers on its promise once it is dialed in to your body.