HOW DO I ADD A DAY/ NIGHT CYCLE?

It is actually quite simple :D
You will however if your eventing it need a few common events and switches depending on how in depth you want to go with it.
1st. Make a common Event that requires a switch (Probably one of the first one's that turn on) to be on and set it to parallel process.
2nd. Figure out how long you want each cycle to be. For example lets say I want three cycles morning, mid-day, and night time to pass between every 1 min in real life time ( just an example.) Ok lets say it starts morning have the screen change colors with the change screen color tone. Now there are several different ways to do this so I'm gonna split it to two different ways A, and B and C.

A: Set a variable for play time but preferably a timer, and under it set a conditional branch for the intervals of time. Note this could get complicated and long lol, but u could reset the variable

B: Make a bunch of wait commands then turn on a switch.

C. Make a variable that goes 1-3 for this case. Make another variable that tracks player time like A but when the intervals happen have it add to the other variable. This makes it much cleaner.

Either way the new switch will then turn on a new common event. In this case Mid-day.

So you say what about if I go into caves, it cant be daytime in there? Well for that just turn off all switches that work with the common events going in and turn them back on when leaving.

So yea really I would recommend going B or C. If you need any help I'll post some screenies.

Thanks Hope it Helps.