If your trailer is equipped with electric brakes, you can adjust the amount of braking force by turning the knob on the brake controller. The factory setting for most controllers is about halfway to full power. If you find that your trailer is stopping too slowly, or if the brakes seem to be dragging, you can turn the knob clockwise to increase the amount of braking force. Conversely, if your trailer seems to be stopping too quickly or if the brakes are locking up and skidding, you can turn the knob counterclockwise to decrease the amount of braking force.
It's important to experiment a bit to find the right setting for your particular trailer and load. A good starting point is to set the controller so that when you apply moderate pressure on the brake pedal, your trailer slows down at a rate that feels safe and controlled. From there, you can make adjustments as needed depending on how your trailer responds.