You have to sign in with your GitHub credentials. You are then forwarded to authorize the app in your GitHub account.
You need to allow the app to access your account in order to see your notifications.
You need to allow the app to access organisations your are part of separately. You can do this by requesting to auhtorize the app within your organisations.
This needs to be done by an administrator of the organisation.
Just click on the notification you want to view and your are redirected to the notification within your browser.
Your notifications are frequently updated. If you have received a new one the app icon shows an indicator.
If you have further questions or feedback send a message email@example.com