These rules were found on ArinTheSimsBlog (tumblr.com)
Allowed: Nothing but CC and the cheats “cas.fulleditmode” and “freerealestate on”.
1) To begin with, create one female young adult Sim as your main character. The looks and attires don’t matter. Give your Sim the Self-Assured and Ambitious traits. The third trait is up to your choice but it can’t be the Active or Genius traits.
Recommended: Create Taylor Swift’s character Catastrophe.
2) After creating your sim and moving them in a house, you can now start looking for an STBE (soon-to-be-enemy) BFF. For out antagonist, create another female young adult Sim. Give her the following traits Mean and Ambitious. The third trait is up to your choice. The looks and attires don’t matter.
Recommended: Create Selena Gomez’s character Arsyn.
3) Try to get to know your STBE more and more, and become best friends forever with her.
4) Remain BFFs with your STBE for 7 sim days.
5) After 7 sim days, start to perform mean and/or mischief actions on your STBE and finally become enemies.
6) This point is where you start to gather around your squad. Be good friends with 6 different Sims and manage to add them in to your household. Your squad has to have all the 6 people mastered in a particular skill. (eg. A Sim mastered in Gardening, and another mastered in Painting)
Recommended: Gather your squad in the order we are introduced to the characters who are walking along with Taylor in the final scene. The characters and the skills which they have to master (and which mustn’t be changed if you are following the recommendations) are as the following:
Dilemma (Sereyah) Programming
Slay-Z (Gigi Hadid) Rocket Science
Homeslice (Martha Hunt) Handiness
Mother Chucker (Cara) Logic
Cut Throat (Zendaya) Mischief
The Crimson Curse (Hayley Williams) Fitness
7) You first have to have your entire squad mastered in their skills, AND THEN you can start mastering in ALL SIX skills with YOUR MAIN CHARACTER. Catastrophe got help from her friends to improve herself, you remember?
8) Once your main character has mastered all the six skills, she and her squad can now fight with the evil. Go find your enemy in her house and choose the “Fight!” interaction on her UNTIL you at least win once.