how to do image crop in sanity.io using hotspot feature

Question

io I need to know that how to do image crop in sanity.io using hotspot feature. I searched a whole for this but I didn't find any example for it. can any one help me from this here is my code :

                       <img
                        src={sanityUrlFor(
                          value.mainImage?.asset,
                          currentCountryData.code
                        )
                          .width(600)
                          .height(600)
                          .url()}
                        alt=""
                        className={`${styles.bigImage} cropped-img`}
                      />

please do a example code because i found a documentation but I don't know how to use that crop method.