Outdoor Secrets Seasonal Progression

For the seasonal Progression schedule in the Outdoor Secrets Companion is it Fall, Winter, Spring?  Fall, Spring, Summer? It looks like it is divided into 3 terms, so just wondering which seasons those three terms coordinate with? I was thinking about starting it now for the summer, but wasn’t sure where to start- if I should start with the term 3 schedule for summer, then do the term 1 1 and then 2 schedules?