There are not many text walkthroughs for this game.
There is one at Gamefaqs here
https://gamefaqs.gamespot.com/pc/934985-gray-matter/faqs/62036but it is not better than MaG's walkthrough.
I think this game may deliberately have been made so it plays slightly differently every time you play, meaning things will be available in a different order. Supposedly this is to increase "replayability" but it means you can't follow a walkthrough step by step. That is why MaG included the suggestions Marian quoted in her walkthrough. It is not possible to make a step-by-step walkthrough when the game deliberately makes the order you can do things in different every time you start a new game.
If you can't deal with that, and want a game with a walkthrough that can be followed step by step, perhaps this is not the game for you. You can always watch a YouTube playthrough if you're interested in how the story turns out.