How is our understanding of the Oort Cloud's population primarily derived?

Studying the long-period comets

Because the Oort Cloud is too distant and faint for current instruments to resolve directly, knowledge about its contents is predominantly inferred by observing the bodies that occasionally plunge inward. These inbound objects are specifically identified as long-period comets. These comets are considered direct emissaries from the Oort Cloud, carrying the chemical signatures representative of the solar system's primordial past. Astronomers construct statistical models based on the trajectory and characteristics of these few perturbed comets to reconstruct the nature of the entire massive population residing in the cloud.