I also only got lucky stumbling to Kevin's route and the game gets easier once you get used to where they always show up and go (which is pretty obvious).
However, the game's pretty buggy as hell. I managed to finish Thomas' route, Kevin's and even Ian's without the walkthrough but I experienced a ton of loops and repeated dialogues throughout the whole process of figuring them out. I legit filled up almost all my saves just doing these three routes.
I get not needing a walkthrough as soon as possible since it defeats the purpose of "exploring" the game but it's really easy to understand why others need and want it. I already subscribed to the creator's patreon (to access their other games plus to know if there's a path for Charlie) and got the copy of the cheat map but even then it was confusing. So I'm willing to bet many players who do not have enough patience will get frustrated with the game without the walkthrough.