Check out example codes for "how to fix on GetMouseButtonDown activating UI unity". It will help you in understanding the concepts better.

Code Example 1

using UnityEngine.EventSystems;

void Update()
{
	if (Input.GetMouseButtonDown(0))
    {
         // This line prevents the Code from activating UI
    	 if (EventSystem.current.IsPointerOverGameObject())
                return;
         // Put your code here       
    }
}

Learn ReactJs, React Native from akashmittal.com