By using the passage finish the sentence.
To summarize, the main idea of the system is to match the frequency of the TMD to the inherent frequency of the structure itself if the structure's frequency is 0.2 Hz for example, the TMD should be designed to a frequency that is exactly the same or close to this value, hence "tuned". If this is achieved, then the TMD will be effective and the vibration of the structure will be controlled, likewise, acceleration will subside more efficiently.
A well tuned TMD impacts the acceleration by..