How to create a notification pop up message for the user when they got a new Task/event

In ERPNext, i want a user to get a pop up message about if they got assigned a new task or event by any other user, while they login to their ERPNext desk. Guide me step by step to achieve this process. Or tell me what are the specific modifications should i made to achieve this process.

It’s not easy; you have to override and customize the notification code. If you want to set up a pop notification at the login level, you also have to customize the desk level.

Popup notification if assign event or tasks (without login), provide a similar reference and add your scenario: Bell Notification - #2 by NCP