You can vary things to fit your unique physiology, but for a typical athlete with some background in other sports, but new to running, this system works best.
Season 1 (new to running): One annual cycle focused on building aerobic strength, with six months in foundation, six months in endurance and resilience.
Season 2 (advanced beginner): Two six-month cycles focused on doing some races and getting faster, with three months in foundation, two months in endurance and resilience and one month in workout.
Season 3 (more experienced trail runner): Two six-month cycles focused on doing more races, with two months in foundation, two months in endurance and resilience and two months in workouts and taper.
Season 4 and beyond (very experienced trail runner): Three four-month cycles focused on reaching potential, with one month in foundation, one month in endurance and resilience and two months in workouts and taper.
And don’t worry. Chasing your potential takes years, so keep believing!