Hey! We know that currently the tutorial section is a bit poor in the explanation and the game does not give any hint about that, we're currently working to add feedback in-game to make it more clear, also we're planning to explain better how to play in game.
Now I'm gonna answer to the problem you had: the room on the left yes, is about exactly what you said, the souls are the ingredients.
If you point the mouse over a soul and you are in a certain range within the soul (this lacks a feedback right now), if all of that is done correctly an outline appears around it and by clicking left or right mouse button you pick it up in your hand (depending on the click), when it's in your hand you can throw it by clicking again.
To make orders you have to throw souls in the machines near you when you spawn. If you want to make an order on a machine with less than 3 souls just press E while pointing the machine (it should highlight).
Hope that I did clear things for you, we'll update the itch description ASAP and thanks for the feedback, it helps!