Scripts

I tried creating a DialogScene, and I have some questions. Why is it necessary to specify a hero link or monster link? How can I make the video have a specific duration, because when I run it, I just get a black screen for a second? And another thing: in the camera settings, there are "start camera" and "finish camera." What is "startcameradiff"? And how do you even create effects like movement or attacks? Thanks in advance.