Camera position
Place your phone at hip height, directly in front of you (face-on) or directly behind you (down-the-line). Make sure your whole body is visible, from feet to clubhead at the top of your swing.
Light and background
Film in daylight or good lighting. A calm background without busy patterns helps the analysis track your movement accurately.
Format
MP4, MOV or AVI — most phone videos work directly. Keep the video short: a few seconds before and after your swing is enough.