Hi Nivedita,
You can see an example here on the Docs site.
https://docs.servicenow.com/bundle/rome-application-development/page/script/client-scripts/concept/c...
You use it in a client script to retrieve the entire record of a reference field/variable, then you can use another column on the same record in the script to setValue of another field/variable, etc.
Here's an example which sets the value of a location variable to the location that is on the user record of the requested for.
function onChange(control, oldValue, newValue, isLoading) {
if (isLoading || newValue == '') {
return;
}
var userref = g_form.getReference('requested_for', userLookup);
function userLookup(userref){
g_form.setValue('location', userref.location.toString());
}
}
