Create a document in which you describe in detail the path the player will take to go through the game (successfully) as a list of actions and a description of all the options, characters and locations. Imagine it as a solution or walkthrough of a game guide.
Example:
-You start in your private investigator office, the narrator tells you that you have amnesia and that you are a disgraced detective. There is a safe, a bottle of whisky, a desk, a cat, and a cheap mattress on the floor.
– You pet the cat and that reminds you of your wife, who kicked you out of your place, that’s why you are sleeping in the office.
-The bottle is empty, bitter monologue
-You can’t open the safe without a key
-You open the desk drawer, and find a key inside it
-You open the safe with the key
-You pick up the gun
-You kill yourself
-The end