This code change the number of time that passed in general
(the time that you see on your save file once you have saved).
Don't activate the code, but instead add it to your bookmark, so you can edit it on the fly.
To calculate the time, you need to convert hours&minutes into seconds, you can use
that calculator here to do it.
For example, 99h59m would be a whole 359940 seconds.
The game maximum time is 99h59m, you can of course play more time than that, but only 99h59m will be recorded on your savefile
(see screenshot).