The next time you watch a movie, look to see how that movie introduces the hero and villain. Most movies introduce the hero first and then the villain. In “Rocky,” we first see Rocky fighting another boxer in a dingy gym. In “WALL-E,” we first see WALL-E roaming around a desolate Earth surrounded by piles of garbage. In “The Invisible Man,” we first see the hero sneaking away from her abusive husband.
Introducing the hero first makes it easy to know who the hero is, what he or she wants, and why we should root for this particular hero. However, occasionally a movie introduces the villain first.
In “Star Wars,” we first see Darth Vader catching up to and eventually boarding Princess Leia’s starship. In horror movies, we often see the villain before we see the hero because this creates a sense of impending doom.
In “It Follows,” we first see a woman running from an unseen attacker as she hides by the beach. Then the next morning her dead body is mangled.
In “Get Out,” we first see a black man walking down the street and getting attacked by an unknown assailant.
So in your own screenplay, who will you introduce first? Try introducing the hero first so audiences know who to root for and what the hero wants. Then try introducing the villain first so audiences know who to fear and what impending danger is waiting the hero.
In general, action, mysteries, and horror stories tend to introduce the villain first while romance, comedy, and drama stories tend to introduce the hero first.
There’s no right or wrong way since you have to introduce both the hero and villain eventually. What matters is what’s right for your screenplay.