Hints: Darker Doki
First, read through the story like in a normal Choose Your Own Adventure book. There should be some information you can pick up along the way.
Group the colored letters based on their colors, and order them by the order in which they would be seen in a “Choose Your Own Adventure” path.
Stuck after first cluephrase:
Think about what “unreachable content” might be, and double-check what paths you took through the book.
Stuck on final cluephrase:
Look carefully through the puzzle for something that could be considered extraneous content.