1. Determine the length of the lever: the length of the lever refers to the distance between two fulcrums, which can be measured with a ruler or other measuring tools.

2. Determine the direction of the force: the position and direction on the rod, and define the magnitude and direction of the force.

3. Calculate the arm of force: the arm of force is the distance perpendicular to the lever, and the length of the force line minus the distance from the point where the force is located to the fulcrum is the length of the arm of force.

4. Using the concept of moment arm, the problem is solved by setting a formula: booster is a simple lever system. In the case of force balance, the relationship of equal torque can be obtained according to the lever principle. Therefore, the definition of booster can be used for mathematical expression, and the mathematical relationship between the force applied along the booster and the acting torque can be obtained.