Horror novels involve a circumstance, for example a number of people are trapped by a huge snowfall in a ski lodge. The interaction of these people, create the suspense when things happen, things that normally do not happen. Mis-direction, a trail in the snow, heightens suspense. A scream or commotion (the tractor out back roars, people dash to find out why) is the distraction to allow a person to vanish. The resulting search provides false clues. More people vanish or die. More false clues. Then an early clue shines brightly, even though discounted earlier. This clue points to the problem, the discovery. The rest is: can the remaining few solve the problem, the escape. If it were Stephen King, only one survives (lol).
Smiles
Bob
These bolded simple elements are the basis of most horror stories, cut and slash, situation, ghost, creature, or psycho.
The cast:
The MC (last alive) is the investigator, the one who has the open mind
The innocents (usually first to go)
The sceptic creates confusion and tension (next to go)
The over the top religious/paranoid/hungry, etc creates division and doubt, opposing plans/actions
The normal joe - strong but scared, creates the fear with country joe tales
The professor who is used by the author to explain away the correct clue