FMB's sound journeys run from 12 minutes, the shortest, to 50 minutes, the longest. Check the length shown for your chosen sound journey in the app before you start, and set aside that block of time without interruption — headphones on, letting the session run end to end rather than skipping around.
A rough average for noticeable results is two to three sessions a week, for three to four weeks in a row — everyone responds at their own pace, and some people notice a shift sooner than others. If you've been listening steadily for a stretch, take a break of a few weeks before starting again; it keeps your brain from settling into the pattern and losing some of the effect.
FMB is a wellness product, not a medical device. It does not diagnose or treat any condition.