Position the hair clipper upside down. The pointed side should face your skin. Keep your face and the clipper straight, and start the machine to set the lines. This is known as 'defining the sideburns'.
2. Now you have a line that serves as a guide for your further work. Shave off all beard hairs outside the line evenly.
3. When you repeat the procedure on the other side, use a mirror or a second person to check that you create a line symmetrical to the first side.