Here are the basic of how to use callbacks and expose functions from the plugin.
To access the API functions, call the $tawkMessenger anywhere in your components. Upon using the tawk-messenger-vue-2 it will auto register the global scope.
this.$tawkMessenger.toggle();
You can listen on events emitted by the plugin, It must be exactly match the name used to listen to that event, you can see the list of events here.
this.$tawkMessenger.$on('load', () => {
// place your code here
});
You can see the list of APIs in API reference.