Check out example codes for "unity adding component to another gameobject". It will help you in understanding the concepts better.

Code Example 1

//referencing a gameobject
public GameObject exampleObject;
private Rigidbody rb; //example of a component

public void Awake() {
	// adding a Rigidbody component to exampleObject
	rb = exampleObject.AddComponent<Rigidbody>();
	// referencing an existing Rigidbody component in exampleObject
	rb = exampleObject.GetComponent<Rigidbody>();

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