Each of the key character types plays a specific role in a story, and there are five which you need to carefully craft into the fabric of your narrative, when designing your story. The protagonist, the antagonist, the mentor, the ally and the love interest.
By the time JOKER reached the screen, director Todd Phillips had rearranged the opening scenes and they were no longer in the same sequence as they were in his original screenplay. He also interestingly added an opening scene that is not in the screenplay at all.
For the audience to care about a character, they need to feel what the character feels and vicariously experience the emotions they experience. The quickest way to get them to do this is to provide them with insight into the way the characters interact with their world, before they see them making important decisions.
Learn how to create a story and where best to locate it. Acquire the skill to create leading characters that have purpose. Discover the difference between obstacles and complications, and procure the ability to recognise and construct crucial structural beats.
Scary movies are hard to write. The Horror genre is sometimes looked down upon by audiences and screenwriters because of their low budgets, exploitative cheap thrills and over-use of blood & gore.