Just turn it on and glide it over the area you want to trim!
You can use your Trimmer or Trimmer Plus with the guide comb to achieve your desired hair length - or without it for a closer trim.
Always ensure you angle the blade and trimmer head flat and parallel to the skin. This will allow a smooth and comfortable glide across the area while avoiding nicks and tugs.
Please do not position the blade tip directly perpendicular to your skin (i.e., stabbing position).
You can find a detailed step-by-step guide here and a quick demo here.