We've already established that pages have a list of actions that is triggered in a linear fashion from top to bottom. So how do you create story branches?
One way is to use "threads". A thread is a seperate list of actions that can be played at any time in a page. When a thread is played the actions of that thread will be triggered. When all of the actions in a thread have been triggered, the game will return to where the thread was initially played in the page.
Fig 1: The flow of triggering actions is interrupted by a thread.
To add a thread to a page, right-click on it in the Navigator and select Add thread.