Hello! To enter each route, you need to make a combination of certain choices. One thing players usually overlook is that choosing if you are the one to give the kiss, or the one you receive it, has a major impact in which routes will be available in the following chapters (that's why some characters are automatically ruled out in your playthrough).
We understand if you don't want to play the whole game again, but we always encourage to do so because part of the fun lies exactaly on that (we work really hard on making the script really different and replayable after all 🥲). The plot of the game revolves around "finding out" who was the kisser/who did you kiss, so simply stating which choices to choose to get one result or another might take the fun out of it at this stage.
Thank you for playing! And thank you for letting us know which points of the game you found confusing, that helps us reflect about our own work 😊