Free background extension how to use in my case

I collect data from my website to my app as shown in this img:

but i want to notify user when ever i change my data that the app receive ( if the app is in background or close ) as shown data is receive in label 2.

Now i want to use a background extension to process the background function and show notification when ever receive data is change.
I am using the free background extension.But no idea how to start and use.

A post was merged into an existing topic: Background Tasks extension