I am going to make a real life horror aventure with friends! need help for scares!

[Roenlond]

The plan:
1. Find a piece of paper which looks old or make it look old (yellowish paper). Perhaps you could iron it to make it look older.
2. Make & Print an article from a newspaper, dated 50 years back which is written in an old tone language wise. The article describes a lumberjack comitting 3 gruesome murders with his chainsaw.
3. Leave trails of items which could belong to a lumberjack at that time. These things are then slowly found during the night as people explore the house.
4. When they are adequately psyched up you have locked all of the doors and cut the power.
5. Wait 20 seconds.
6. Start your chainsaw.
7. Panic will most likely occur so be careful that you do not accidentally harm someone

Good luck have fun

That sounds amazing and it'd probably scare people a lot more than just random events without any real linkage between them.