That sounds like you're looking for a guide for Shiny Days , which can refer to a few different things depending on your interests.
series. A walkthrough for this usually covers character routes (like Setsuna or Kotonoha) and decision trees to reach specific endings. Shiny Days (Pokemon) shiny days walkthrough guide
Essential Patches: For the most stable experience, ensure you have applied the latest Restoration and Fix Patches available via community forums like Fuwanovel. That sounds like you're looking for a guide
Choices: