There will be random 4 digit numbers throughout the story in some scenes, I don't think they're that hard to spot. I decided to have some fun while watching a movie and just brute force my way going up one digit and made it to 0350 and found only 2 scenes.
There is an icon that shows when you have an item equipped at the bottom right, you have to make sure you go to liquid corp website to equip the items.
You need to go the the liquid corp to equip. You use scroll wheel or number keys 1-4 to swap items, there is also an icon on the bottom right when you have something equipped.
You actually need to make sure you equip the bottle in your hand when you find the filling station then once you fill it, find the table and hold it out again where you put it.
You have to go down into the basement and interact with one of the doors with the puppet with you, I think its after you help one of the girls a few times
