Marble Hornets and TribeTwelve-esque stories seem to have a pattern.
1. The protagonist's friend has gone missing/died, and he has old tapes of him and decides to look through them.
2.Things go downhill. He starts seeing Slenderman in the tapes, and starts investigating. He starts seeing Slendy himself. (Example: Jay investigates Alex's house.)
3. The descent into madness begins. He slowly goes mad, leaves his house, gets his account hacked, and checks into a fucked up hotel.
4. ??????????????????? ( This is where the story is supposed to end. However, I haven't seen this happen yet in any series.)
They all make one mistake. At around step 3, the story focuses less on what happened to Alex or Milo, but on random hacked videos and videos of him running away from Masky or Slenderman.