Using your Thomson X4 mountain bike stem is straightforward. First, make sure the bar clamp diameter of 31.8mm fits your bike's handlebars and the stem clamp diameter of 28.6mm fits your bike's steerer tube. Loosen the bolts on the stem, place it on the steerer tube and handlebars, then tighten the bolts gradually and evenly. Check that the stem is at the right angle (0 degrees in this case) and the stack height of 41 is suitable for your riding position. When riding, you'll notice better control and steering. As for maintenance, keep it clean by wiping it with a dry cloth after each ride. If it gets dirty, you can use a mild soap and water solution. Avoid using harsh chemicals. Check the bolts regularly to make sure they're tight but don't over - tighten them as it could damage the stem. If you notice any signs of wear or damage, stop using it and have it checked by a professional.