“Bounding box drawing” and “Outline drawing” using React.js and Cesium.js

Hi,
I would like to implement “Bounding box drawing” and “Outline drawing” using React.js and Cesium.js. When the user label “Bounding box” or “Outline”, the JS will return the coordinates as response.
I know little about “Cesium.js”, so would you pls help to give me some suggestions? Thanks!