The easiest way to send a notification is using a "welcome notification". Alternatively, people can use triggered notifications to send a notification after someone subscribes. If you’d like to go that route, it requires a few extra steps.
The first step is to record the user subscribing as a custom event. Below is a snippet you can use. This snippet will track the Event Category "User" and Event Action "Subscribed" for all new push subscribers.
Now, create a "Triggered Notification" and specify the trigger to be the event set in Step 1. In our example above, we used Category "User" and Action "Subscribed". Event label can be left blank.
Then, set the delay to as long as you want in seconds, for example: Set the delay to 10800 (that’s 3 hours in seconds)
And that's it! Once you save, it will now send a notification that is triggered after somebody subscribes. If you have any questions, please reach out to firstname.lastname@example.org