Switches are the most basic form of controlling the progression of a game however I see a lot of people who use bad switch practices and or just plainly don't know how to use them. So In this tutorial I will go over several Types of Switch based progression systems. Hopefully this guide can give you a better Idea on how to handle your story with Switches.
Now I know a lot of people don't know how switches and conditions work so lets start there.
An Introduction to Switches
A switch is literally nothing more that something that just marks when you want certain actions and story to be used. And an event that contains any part of the story or game that is hidden or not accessible at the start of the game needs a switch turned on before it is used.
In this example the event need a switch called Intro1 turned ON to start and tell the player an important message.
Branching Story progression is where your player is given a choice and depending on that choice it will open up 1 and only 1 of 2 or more possible story lines with their own chains of switches. This is not to be confused with Parallel Progression which is different king of progression that will be discussed later. So in Branching progression after the player makes a Choice you turn on one of the 2 possible switches and leave the other off, and turn off the Switch before hand. This can be useful for when the player has to make huge story decisions like go west through the army of demons or north and try to go around them.
Converging Progression is where Parallel ALWAYS ends up, but branching can also end here too. Converging progression is where you take all the current On Switches for the story and turn them off before turning a new single switch on. Then it resumes from here with Linear Progression until another Branch or Parallel happens.
The final type of progression to cover is the one that does not follow the main story or has no main story. Side Questing is a collection of smaller Linear Progressions that the first Switch in a chain is started by talking to a character event then after a few tasks the chain ends. This is a more free form way to have progression but each quest should follow the general guidelines of the other types.