hey mate
normally horror stories start with a normal begining, for example:
"catch" yelled jack, throwing a baseball at me.
and then they go crazy, for example:
a sound had awoken me a soft dripping sound... drip.. drop.. i went outside my room and turned on the light. it was silent in the house apart from that dripping sound..... i went into the hallway and just as i was walking under the light bulb a drop of bright red blood droped on me from above. i froze, then i slowely looked up...
and then the end consists of either:
a) a twist (an unexpectad ending)
b) a jump scare
or
c) a chilling ending
hoped this helped making you your story