Tycoon Management game making help

Hello everyone. I am currently trying to make a tycoon game; one such as Disco Zoo (by Nimblebit) or any other game where the aim is to gain money whilst time passes, even while the app is closed. I have never actually experienced making this type of game and I would appreciate as much help given as possible. I believe I can try, but I'm unsure I will succeed at allowing the time go by in the background of the game while the player is not using it. This is a mobile game which, I think, makes it easier to make. Thank you for your help. It would be amazing if I completed this game. 

I think it is possible with this extension.

You could save the timestamp (that is, the number of seconds since 1970) when the player quits the game.

When the player re-opens the game, you calculate current time stamp minus saved time stamp to determine how many seconds has passed since the last time he played. You can then determine how much the player earned in that number of seconds (there is also a block to convert them in minutes or hours if you prefer).

I did not actually use that extension, so I can't tell for sure if it'll work, but it should.
And don't forget that the player would be able to cheat by changing the time of his device.

I think it is possible with this extension.

You could save the timestamp (that is, the number of seconds since 1970) when the player quits the game.

When the player re-opens the game, you calculate current time stamp minus saved time stamp to determine how many seconds has passed since the last time he played. You can then determine how much the player earned in that number of seconds (there is also a block to convert them in minutes or hours if you prefer).

I did not actually use that extension, so I can't tell for sure if it'll work, but it should.
And don't forget that the player would be able to cheat by changing the time of his device.

Thank you so very much. I have yet to try it but I assume that is the way they do it in 'Animal Crossing.'