Start an Alert by opening page with Flutter web

I want to build an Flutter alert into my web app and when i open the website i want to pop it up immediately. The alert is build with the rflutter_alert package.

Does somebody have a solution to open this alert automatically?

Thanks for any answer.

Code of the Alert

_onBasicAlertPressed(context) {
Alert(
  context: context,
  title: "JOJOJO",
  desc: "Flutter is more awesome with RFlutter Alert.",
).show();

}