While there is no single "official" PDF manual titled "Professional Mixing and Mastering" provided by Image-Line, there are several comprehensive resources and downloadable guides that cover these features in depth. The FL Studio Mixing & Mastering Bible : A high-level comprehensive guide

: Assign every instrument to its own mixer channel. Labels and color-coding are essential for navigation. Professional mixes typically start with conservative levels between -6 to -12 dB to prevent clipping. Spectral Management (EQ)

That gap between a "bedroom beat" and a "radio-ready record" is bridged by two critical processes: and Mastering .