How to have a real-time countdown timer that continues even if the app is exited? (For someone who has no idea about servers and connecting to the internet via code)

Looking at earlier similar questions, it seems that people always say to use the internet to get time (and proceeding to give no sample code). However, I have no knowledge about any of that, and Googling it seems to bring about results that only people with a background in programming can understand. I really don’t know how to get time from a server. This is for a free gift timer. Could anyone please provide an answer that can give some barebones sample code, or at least sources where one can learn to do it?

Save the time when the timer starts, and when the app is ran again, do CurrentTime - SavedTime to get the time passed, this should allow you to get all the info you need for the timer.